KNP Complex Fire

{{Further|Climate change in California|History of wildfire suppression in the United States}}

The KNP Complex Fire took place during a severe fire season for the western United States, and particularly for California. During the state's 2021 wildfire season nearly 2.6 million acres ({{convert|2,600,000|acres|ha|abbr=out|disp=output only}}) burned: the second largest area on record after 2020.{{Cite news |last=Wigglesworth |first=Alex |date=December 13, 2021 |title=Southern California spared major fires as storms end an unprecedented season |work=Los Angeles Times |url=https://www.latimes.com/california/story/2021-12-13/winter-storms-poised-to-end-california-wildfire-season |url-status=live |access-date=March 8, 2023 |archive-url=https://web.archive.org/web/20230213223704/https://www.latimes.com/california/story/2021-12-13/winter-storms-poised-to-end-california-wildfire-season |archive-date=February 13, 2023}} The national preparedness level hit the maximum level of 5 on July 14 and remained there until September 20, the longest period on record.{{Cite report |url=https://www.nifc.gov/sites/default/files/NICC/2-Predictive%20Services/Intelligence/Annual%20Reports/2021/annual_report_0.pdf |title=Wildland Fire Summary and Statistics: Annual Report 2021 |date=2021 |publisher=National Interagency Coordination Center |access-date=August 1, 2023 |archive-url=https://web.archive.org/web/20230715080906/https://www.nifc.gov/sites/default/files/NICC/2-Predictive%20Services/Intelligence/Annual%20Reports/2021/annual_report_0.pdf |archive-date=July 15, 2023 |url-status=live}}{{rp|page=6|quote="The national PL remained at five through September 20, spanning 68 days, which is the longest period since PL record keeping began in 1990."}} Officials took drastic measures to try and limit new ignitions: between August 31 and September 15, the U.S. Forest Service’s Pacific Southwest Region closed all of California's national forests to public use because of fire conditions.{{Cite news |last=Yee |first=Gregory |date=August 30, 2021 |title=Forest Service officials confirm all California national forests to temporarily close |work=Los Angeles Times |url=https://www.latimes.com/california/story/2021-08-30/officials-to-close-all-california-national-forests-a |url-status=live |access-date=March 9, 2023 |archive-url=https://web.archive.org/web/20230215213839/https://www.latimes.com/california/story/2021-08-30/officials-to-close-all-california-national-forests-a |archive-date=February 15, 2023}}{{Cite news |last=Victor |first=Daniel |date=September 15, 2021 |title=California will reopen many of its national forests, but fire threats remain. |language=en-US |work=The New York Times |url=https://www.nytimes.com/2021/09/15/us/california-wildfires-updates-forests.html |url-status=live |access-date=March 9, 2023 |archive-url=https://web.archive.org/web/20230126010817/https://www.nytimes.com/2021/09/15/us/california-wildfires-updates-forests.html |archive-date=January 26, 2023 |issn=0362-4331}}

In the decades preceding the fire, average temperatures in the Sierra increased measurably even as precipitation did not. This trend was driven partly by climate change. Climate change and consequent warming in California has helped produce hotter and more severe droughts,{{Cite news |last=Borunda |first=Alejandra |date=September 17, 2020 |title=The science connecting wildfires to climate change |work=National Geographic |url=https://www.nationalgeographic.com/science/article/climate-change-increases-risk-fires-western-us |url-status=dead |access-date=August 21, 2023 |archive-url=https://web.archive.org/web/20230819194530/https://www.nationalgeographic.com/science/article/climate-change-increases-risk-fires-western-us |archive-date=August 19, 2023}}{{Cite news |last=Magill |first=Bobby |date=July 29, 2016 |title=Climate Change Fingerprints Are All over California Wildfires |work=Scientific American |url=https://www.scientificamerican.com/article/climate-change-fingerprints-are-all-over-california-wildfires/ |url-status=live |access-date=August 21, 2023 |archive-url=https://web.archive.org/web/20221206072535/https://www.scientificamerican.com/article/climate-change-fingerprints-are-all-over-california-wildfires/ |archive-date=December 6, 2022}} such as the one California endured between 2012 and 2016. Acute stress from that drought killed many trees in the Sierra Nevada, particularly at middling elevations.{{Cite web |title=Climate Change |url=https://www.nps.gov/seki/climate-change.htm |url-status=live |archive-url=https://web.archive.org/web/20230222231548/https://www.nps.gov/seki/climate-change.htm |archive-date=February 22, 2023 |access-date=March 14, 2023 |website=Sequoia & Kings Canyon National Parks |publisher=National Park Service}}File:MeanTempPrecip SEKI shaded.jpgThe lack of water also crippled trees' abilities to resist the predations of bark beetles, which resulted in "greatly elevated mortality" for many major tree species in Sequoia National Park, including the ponderosa pine, the sugar pine, the incense-cedar, and the white fir. Annual tree mortality rates nearly doubled in the park just between 1983 and 2004. A park representative estimated in 2021 that Sequoia and Kings Canyon National Parks held over one million beetle-killed trees that were helping drive the KNP Complex Fire.{{Cite news |last=Wigglesworth |first=Alex |date=September 25, 2021 |title=Crews scramble to make progress against California wildfires |work=Los Angeles Times |url=https://www.latimes.com/california/story/2021-09-25/crews-scramble-to-make-progress-against-california-wildfires |url-status=live |access-date=March 9, 2023 |archive-url=https://web.archive.org/web/20220925205101/https://www.latimes.com/california/story/2021-09-25/crews-scramble-to-make-progress-against-california-wildfires |archive-date=September 25, 2022}}

California saw its second-driest water year ever in 2020–2021, exceeded only by that of 1923–1924.{{Cite news |last=Elamroussi |first=Aya |date=October 20, 2021 |title=California is under a statewide drought emergency as it sees its driest year in nearly a century |work=CNN |url=https://edition.cnn.com/2021/10/20/weather/california-drought-emergency-expanded/index.html |url-status=live |access-date=March 9, 2023 |archive-url=https://web.archive.org/web/20221017105645/https://edition.cnn.com/2021/10/20/weather/california-drought-emergency-expanded/index.html |archive-date=October 17, 2022}} It was the driest ever water year on record for the southern Sierra Nevada, with {{convert|9.9|in|cm|abbr=out}} of rainfall compared to the region's average of {{convert|28.8|in|cm|abbr=out}}.{{Cite news |last=Leonard |first=Diana |date=September 20, 2021 |title=Rain brings fire relief in Pacific Northwest, but winds fan flames in California |newspaper=The Washington Post |url=https://www.washingtonpost.com/weather/2021/09/20/fire-sequoia-california-wind-rain/ |url-status=live |access-date=October 30, 2023 |archive-url=https://web.archive.org/web/20211024200236/https://www.washingtonpost.com/weather/2021/09/20/fire-sequoia-california-wind-rain/ |archive-date=October 24, 2021}} The summer of 2021 was also California's hottest ever recorded.{{Cite news |last=Smith |first=Hayley |date=September 9, 2021 |title=California records its hottest summer ever as climate change roils cities |work=Los Angeles Times |url=https://www.latimes.com/california/story/2021-09-09/california-records-hottest-summer-amid-heat-wave-flex-alert |url-status=live |access-date=March 15, 2023 |archive-url=https://web.archive.org/web/20230227013534/https://www.latimes.com/california/story/2021-09-09/california-records-hottest-summer-amid-heat-wave-flex-alert |archive-date=February 27, 2023}} The hot and dry conditions kept vegetation moisture levels "critically low".{{rp|pages=|page=24|quote="While temperatures remained moderate, fuel moistures throughout the surrounding area were critically low."}}

The drought and dead trees added to the high levels of vegetation that had already accumulated in Sierra Nevada forests. Prior to European-American settlement, frequent fires of lower severity occurred, leaving most sequoia trees unharmed and aiding regeneration in the forest by consuming dry fuels. This ceased in the 20th century when the U.S. federal government began extinguishing every wildfire as a matter of policy. This led to elevated fuel loads in forests, including giant sequoia groves.{{Cite news |last=Jacobo |first=Julia |date=July 14, 2022 |title=How climate change is now threatening the survival of fire-adaptive sequoia trees |work=ABC News |url=https://abcnews.go.com/US/climate-change-now-threatening-survival-fire-adaptive-sequoia/story?id=86618286 |url-status=live |access-date=August 18, 2023 |archive-url=https://web.archive.org/web/20230807012046/https://abcnews.go.com/US/climate-change-now-threatening-survival-fire-adaptive-sequoia/story?id=86618286 |archive-date=August 7, 2023}}{{Cite news |last1=Hill |first1=Avery P. |last2=Field |first2=Christopher B. |last3=Diffenbaugh |first3=Noah S. |date=September 30, 2021 |title=Even fire-adapted giant sequoias can't withstand California's megafires |work=The Hill |url=https://thehill.com/opinion/energy-environment/574763-even-fire-adapted-giant-sequoias-cant-withstand-californias/ |access-date=August 18, 2023 |archive-url=https://web.archive.org/web/20230323123715/https://thehill.com/opinion/energy-environment/574763-even-fire-adapted-giant-sequoias-cant-withstand-californias/ |archive-date=March 23, 2023}}

Not until the 1960s was fire reintroduced to some groves.{{Cite news |last=Borunda |first=Alejandra |date=July 14, 2022 |title=The key to protecting Yosemite's sequoias from wildfires? More fire |work=National Geographic |url=https://www.nationalgeographic.com/environment/article/the-key-to-protecting-yosemites-sequoias-from-wildfires-more-fire |url-status=dead |access-date=March 14, 2023 |archive-url=https://web.archive.org/web/20230205143829/https://www.nationalgeographic.com/environment/article/the-key-to-protecting-yosemites-sequoias-from-wildfires-more-fire |archive-date=February 5, 2023}} While approximately {{convert|30000|acres|ha|abbr=on}} used to burn naturally and annually in the Sequoia and Kings Canyon parks, as of 2022 the parks burned only around {{convert|10000|acres|ha|abbr=on}} annually in prescribed burns.{{Cite news |last=Partlow |first=Joshua |date=August 16, 2022 |title=California's giant sequoias are burning up. Will logging save them? |newspaper=The Washington Post |url=https://www.washingtonpost.com/climate-environment/2022/08/16/giant-sequoias-fire-mariposa-grove/ |url-status=live |access-date=March 14, 2023 |archive-url=https://web.archive.org/web/20230224054723/https://www.washingtonpost.com/climate-environment/2022/08/16/giant-sequoias-fire-mariposa-grove/ |archive-date=February 24, 2023}} Much of the KNP Complex Fire footprint had no recent wildfire burn history.{{rp|pages=|page=24|quote="Most of the fire planning area had no recent fire history."}} A 2023 study identified "old, large-diameter fuels like fallen logs" as the likely culprit for the fire's high intensity after analyzing radiocarbon signatures in samples of the smoke, consistent with prior research demonstrating that fire suppression and the resulting accumulation of fuels have contributed to elevated fire intensities in the Sierra Nevada.{{Cite news |last=Blakemore |first=Erin |date=October 1, 2023 |title=Large trees fueled massive Calif. wildfire that killed giant sequoias |newspaper=The Washington Post |url=https://www.washingtonpost.com/science/2023/10/01/old-large-trees-knp-wildfire-fuel/ |url-status=live |access-date=October 28, 2023 |archive-url=https://web.archive.org/web/20231014225237/https://www.washingtonpost.com/science/2023/10/01/old-large-trees-knp-wildfire-fuel/ |archive-date=October 14, 2023}}{{Cite journal |last1=Odwuor |first1=A. |last2=Yañez |first2=C. C. |last3=Chen |first3=Y. |last4=Hopkins |first4=F. M. |last5=Moreno |first5=A. |last6=Xu |first6=X. |last7=Czimczik |first7=C. I. |last8=Randerson |first8=J. T. |date=August 24, 2023 |title=Evidence for multi-decadal fuel buildup in a large California wildfire from smoke radiocarbon measurements |url=https://escholarship.org/content/qt17x898zk/qt17x898zk.pdf?t=s2exfs |journal=Environmental Research Letters |language=en |publisher=IOP Publishing |volume=18 |issue=9 |pages=094030 |doi=10.1088/1748-9326/aced17 |issn=1748-9326 |archive-url= |archive-date= |access-date=October 30, 2023 |via=IOPscience|doi-access=free }}

File:2021 KNP Complex Fire Colony and Paradise fires.jpg

On the night of September 9, a series of thunderstorms moved through California, generating more than 1,100 cloud-to-ground lightning strikes across the state by the following morning.{{Cite news |last=Jones |first=Judson |date=September 10, 2021 |title=Over 1,000 lightning strikes occurred overnight in California, igniting new wildfires |work=CNN |url=https://www.cnn.com/2021/09/10/weather/california-lightning-wildfires/index.html |url-status=live |access-date=March 8, 2023 |archive-url=https://web.archive.org/web/20220830172518/https://www.cnn.com/2021/09/10/weather/california-lightning-wildfires/index.html |archive-date=August 30, 2022}} Over 200 strikes occurred in Sequoia and Kings Canyon National Parks.{{Cite web |title=KNP Complex Fire |url=https://www.nps.gov/seki/learn/nature/knp-complex-fire.htm |url-status=live |archive-url=https://web.archive.org/web/20230308031434/https://www.nps.gov/seki/learn/nature/knp-complex-fire.htm |archive-date=March 8, 2023 |access-date=March 8, 2023 |website=Sequoia & Kings Canyon National Parks |publisher=National Park Service}} On September 10, three lightning-ignited fires were discovered in Sequoia National Park. One of them, the Cabin Fire, was found near Dorst Creek and fully contained at only {{convert|1.25|acres|ha|abbr=on}}.{{rp|pages=290–292|page=|quote="The Cabin Fire (36° 40.254, -118° 48.330), located near Dorst Creek... ...in foothill chaparral."}}

The other two fires were the {{convert|4|acres|ha|abbr=on|adj=on|spell=in}} Colony Fire near Colony Peak, burning in a mixed conifer forest west of the Giant Forest and north of the Kaweah River, and the {{convert|1/4|acres|ha|abbr=on|adj=on|spell=in}} Paradise Fire west of Paradise Creek, south of the Kaweah River and burning in chaparral in rugged terrain.{{Cite report |url=https://www.nps.gov/seki/learn/nature/upload/2021_BAER_KNP_EmergencyStabilizationPlan_508_2.pdf |title=Emergency Stabilization & Rehabilitation Plan: KNP Complex, Sequoia and Kings Canyon National Parks, CA |date=November 5, 2021 |publisher=National Park Service |pages=[https://www.nps.gov/seki/learn/nature/upload/2021_BAER_KNP_EmergencyStabilizationPlan_508_2.pdf Part 1], [https://www.nps.gov/seki/learn/nature/upload/2021_BAER_KNP_EmergencyStabilizationPlan_508_1.pdf Part 2] ([https://web.archive.org/web/20221119001959/http://www.nps.gov/seki/learn/nature/upload/2021_BAER_KNP_EmergencyStabilizationPlan_508_1.pdf Part 2 archive]) |access-date=March 8, 2023 |archive-url=https://web.archive.org/web/20221119002015/https://www.nps.gov/seki/learn/nature/upload/2021_BAER_KNP_EmergencyStabilizationPlan_508_2.pdf |archive-date=November 19, 2022 |url-status=live}}{{rp|pages=290–292|page=|quote="The Cabin Fire (36° 40.254, -118° 48.330), located near Dorst Creek... ...in foothill chaparral."}} Campgrounds and park roads nearby closed and suppression efforts began, with handcrews on the ground and water and fire retardant drops from the air. With the combination of difficult terrain and dry weather conducive to fire spread, park officials warned that "the fires have spread potential and could affect operations in the coming days or weeks."{{Cite web |date=September 10, 2021 |title=Parks Fight New Wildfires Ignited by Lightning Storm |url=https://www.nps.gov/seki/learn/news/parks-fight-new-wildfires-ignited-by-lightning-storm.htm |url-status=live |archive-url=https://web.archive.org/web/20221020190320/https://www.nps.gov/seki/learn/news/parks-fight-new-wildfires-ignited-by-lightning-storm.htm |archive-date=October 20, 2022 |access-date=March 14, 2023 |website=Sequoia & Kings Canyon National Parks |publisher=National Park Service}} The Colony and Paradise fires grew overnight to {{convert|72|acres|ha|abbr=on}} and {{convert|32|acres|ha|abbr=on}} respectively, with no containment.{{Cite web |date=September 11, 2021 |title=Wildfires in Sequoia National Park Growing, Closures Underway |url=https://www.nps.gov/seki/learn/news/wildfires-in-sequoia-national-park-growing-closures-underway.htm |url-status=live |archive-url=https://web.archive.org/web/20230308031448/https://www.nps.gov/seki/learn/news/wildfires-in-sequoia-national-park-growing-closures-underway.htm |archive-date=March 8, 2023 |access-date=March 14, 2023 |website=Sequoia & Kings Canyon National Parks |publisher=National Park Service}} On September 11 the two fires, though still discrete, were christened the KNP Complex Fire.File:Wrapping_Historic_Entrance_Sign_(a224b015-32d1-4fdb-81fe-3a161197c6d6).jpg

Ground crews on the Colony Fire were beleaguered by {{convert|6|ft|m|adj=on|spell=in}} flames and many hazardous snags. Meanwhile, the Paradise Fire's challenging location mid-slope with no safety zones or easy access caused officials to resort to an aircraft-only strategy, hoping to use water and fire retardant drops to keep the fire north of Paradise Ridge and south of the Kaweah River.{{rp|pages=23–24|page=|quote="Instead, aircraft were directed to use water and retardant drops as part of an indirect strategy with the goal of keeping the Paradise Fire south of the Kaweah River and north of Paradise Ridge."}} By September 13, the area burned surpassed {{convert|200|acres|ha|abbr=on}} for the Colony Fire and {{convert|800|acres|ha|abbr=on}} for the Paradise Fire. Evacuations were ordered for the Mineral King area, and warnings instituted for Three Rivers. The response was still hampered by the rough terrain, as officials noted that ground access to the Paradise Fire had proved "impossible" thus far. Only 130 personnel were engaged on the incident.{{Cite web |date=September 13, 2021 |title=KNP Complex Update for September 13, 2021 |url=https://www.nps.gov/seki/learn/news/knp-complex-update-for-september-13_2021.htm |url-status=live |archive-url=https://web.archive.org/web/20211025201144/https://www.nps.gov/seki/learn/news/knp-complex-update-for-september-13_2021.htm |archive-date=October 25, 2021 |access-date=March 14, 2023 |website=Sequoia & Kings Canyon National Park |publisher=National Park Service}}

That night, the Paradise Fire spread down-slope to the north, crossing the Middle Fork of the Kaweah River and the Generals Highway. Park employees at the Ash Mountain Headquarters Complex and in employee housing nearby evacuated.{{Cite web |date=September 14, 2021 |title=KNP Complex Update September 14, 2021 |url=https://www.nps.gov/seki/learn/news/knp-complex-update-9-14-2021.htm |url-status=live |archive-url=https://web.archive.org/web/20221114191358/https://www.nps.gov/seki/learn/news/knp-complex-update-9-14-2021.htm |archive-date=November 14, 2022 |access-date=March 14, 2023 |website=Sequoia & Kings Canyon National Parks |publisher=National Park Service}} Both fires expanded considerably over the course of the following day (September 14), taking the Paradise Fire's total burned acreage to more than {{convert|5900|acres|ha|abbr=on}} and the Colony Fire to more than {{convert|1100|acres|ha|abbr=on}}. Sequoia National Park closed to the public.{{Cite web |date=September 15, 2021 |title=KNP Complex Update – September 15, 2021 |url=https://www.nps.gov/seki/learn/news/knp-complex-update-september-15-2021.htm |url-status=live |archive-url=https://web.archive.org/web/20211020144950/https://www.nps.gov/seki/learn/news/knp-complex-update-september-15-2021.htm |archive-date=October 20, 2021 |access-date=March 14, 2023 |website=Sequoia & Kings Canyon National Parks |publisher=National Park Service}}

On September 15 and 16, both fires grew moderately and on every flank. With the arrival of a Type 1 incident management team, the number of personnel on the incident grew to more than 400, even as the combined size of the two fires reached more than {{convert|11000|acres|ha|abbr=on}}.{{Cite web |date=September 16, 2021 |title=KNP Complex Update September 16, 2021 |url=https://www.nps.gov/seki/learn/news/knp-complex-update-september-16-2021.htm |url-status=live |archive-url=https://web.archive.org/web/20220125082359/https://www.nps.gov/seki/learn/news/knp-complex-update-september-16-2021.htm |archive-date=January 25, 2022 |access-date=March 14, 2023 |website=Sequoia & Kings Canyon National Parks |publisher=National Park Service}}{{Cite web |date=September 17, 2021 |title=KNP Complex Update – September 17, 2021 |url=https://www.nps.gov/seki/learn/news/knp-complex-update-september-17-2021.htm |url-status=live |archive-url=https://web.archive.org/web/20211020133920/https://www.nps.gov/seki/learn/news/knp-complex-update-september-17-2021.htm |archive-date=October 20, 2021 |access-date=March 14, 2023 |website=Sequoia & Kings Canyon National Parks |publisher=National Park Service}} As the Colony Fire moved within {{convert|1|mi|km|abbr=out|spell=in}} of the Giant Forest, containing the General Sherman tree and thousands of other giant sequoias, firefighters began to protect specific trees by removing vegetation from around their bases and covering parts of the trees in a protective foil wrap, usually used to protect structures and for firefighters' emergency shelters.{{Cite news |last=Seidman |first=Lila |date=September 16, 2021 |title=Giant Forest trees prepped for flames in Sequoia National Park as KNP Complex fire closes in |work=Los Angeles Times |url=https://www.latimes.com/california/story/2021-09-16/sequoia-giant-forest-trees-prepped-knp-complex-fire |url-status=live |access-date=August 31, 2023 |archive-url=https://web.archive.org/web/20230830230825/https://www.latimes.com/california/story/2021-09-16/sequoia-giant-forest-trees-prepped-knp-complex-fire |archive-date=August 30, 2023}}

File:General_Sherman_with_fire_protection_wrap.jpg in protective foil to stop fire burning into old cavities or fire scars|alt=Six firefighters clad in yellow gear place sheets of silver foil around the tree's base, slightly above the height of their heads.]]

On September 17, the Colony and Paradise fires met and merged in the drainage of the Marble Fork of the Kaweah River. Smoke that had stifled the combined fire's northeastern portion cleared away, and the resulting ventilation allowed the fire to grow. The northern portion of the blaze pushed up and out of the Marble Fork into the Halstead Creek drainage in a {{convert|6500|acres|ha|abbr=on|adj=on}} "extreme head fire run", according to a National Park Service post-fire assessment, burning the entirety of the Suwanee Grove at almost entirely moderate to high severity.{{Cite web |date=September 18, 2021 |title=KNP Complex Update – September 18, 2021 |url=https://www.nps.gov/seki/learn/news/knp-complex-update-september-18-2021.htm |url-status=live |archive-url=https://web.archive.org/web/20221205152300/https://www.nps.gov/seki/learn/news/knp-complex-update-september-18-2021.htm |archive-date=December 5, 2022 |access-date=March 15, 2022 |website=Sequoia & Kings Canyon National Parks |publisher=National Park Service}}{{rp|pages=292–294|page=}} The fire also entered the westernmost edge of the Giant Forest grove for the first time, in the vicinity of the Four Guardsmen trees,{{Cite news |last1=Wigglesworth |first1=Alex |last2=Xia |first2=Rosanna |date=September 19, 2021 |title=Wildfires threatening giant sequoias continue to grow with another red-flag warning day |work=Los Angeles Times |url=https://www.latimes.com/california/story/2021-09-19/wildfires-threatening-giant-sequoias-grow-red-flag-warning |url-status=live |access-date=September 1, 2023 |archive-url=https://web.archive.org/web/20230519100919/https://www.latimes.com/california/story/2021-09-19/wildfires-threatening-giant-sequoias-grow-red-flag-warning |archive-date=May 19, 2023}} but firefighters' protective efforts ensured all four survived.{{Cite web |date=September 19, 2021 |title=KNP Complex Update – September 19, 2021 |url=https://www.nps.gov/seki/learn/news/knp-complex-update-september-19-2021.htm |url-status=live |archive-url=https://web.archive.org/web/20211020151003/https://www.nps.gov/seki/learn/news/knp-complex-update-september-19-2021.htm |archive-date=October 20, 2021 |access-date=March 16, 2023 |website=Sequoia & Kings Canyon National Parks |publisher=National Park Service}} The total burned area reached {{convert|17857|acres|ha|abbr=on}} by September 18 as the complex became one of the highest-priority wildfires in the nation.

The complex slowly grew to just over {{convert|25000|acres|ha|abbr=on}} by September 21,{{Cite web |date=September 21, 2021 |title=KNP Complex Update – September 21, 2021 |url=https://www.nps.gov/seki/learn/news/knp-complex-update-september-21-2021.htm |url-status=live |archive-url=https://web.archive.org/web/20230316144316/https://www.nps.gov/seki/learn/news/knp-complex-update-september-21-2021.htm |archive-date=March 16, 2023 |access-date=March 17, 2023 |website=Sequoia & Kings Canyon National Parks |publisher=National Park Service}} causing Kings Canyon National Park to close. Portions of both parks east of the Pacific Crest Trail in the High Sierra remained open. As crews prepared for the fire's potential arrival in the Lost and Muir sequoia groves, the fire moved through the Giant Forest and reduced in intensity as it met areas that had already been treated with prescribed fire. Meanwhile, California Department of Forestry and Fire Protection (Cal Fire) personnel constructed control lines along Paradise Ridge to help check the fire's growth on its southern end.

File:KNP_Complex_Fire_burns_near_Moro_Rock.jpg visible in the background|left]]

In late September, a high-pressure system settled in place over the area: higher humidity levels and lower temperatures, combined with a thick smoke inversion, stifled fire behavior somewhat even as the lack of visibility prevented aircraft from flying. Despite this, on September 24, fire activity ticked up as flames moved down from the conifer forests into the grass and oak woodlands closer to the visitors center in the foothills, and leapt past firefighters and their control lines on Paradise Ridge. Burnout operations helped catch the fire in the Mineral King Road and Ash Mountain areas. A giant sequoia killed by the fire fell across the Generals Highway, blocking travel between the northern and southern portions of the fire until equipment could be mustered to cut through it.{{Cite web |date=September 24, 2021 |title=KNP Complex Daily Update for September 24, 2021 |url=https://inciweb.nwcg.gov/incident-publication/caknp-knp-complex-/knp-complex-daily-update-for-september-24-2021 |url-status=live |archive-url=https://web.archive.org/web/20230317160634/https://inciweb.nwcg.gov/incident-publication/caknp-knp-complex-/knp-complex-daily-update-for-september-24-2021 |archive-date=March 17, 2023 |access-date=March 17, 2023 |website=InciWeb}}

During the last week of September, the fire grew by several thousand acres per day, driven by gusty west winds. As its footprint increased, mandatory evacuation orders were issued on September 30 for Eshom and Hartland Camp in Tulare County. These orders were expanded on October 1 to include Grant Grove Village, Wilsonia, and Cedar Grove in Kings Canyon National Park, and Big Meadows, Weston Meadows, and Quail Flat areas in Giant Sequoia National Monument.{{Cite news |last=Seidman |first=Lila |date=October 1, 2021 |title=KNP Complex fire triggers flurry of new evacuations, as flames threaten more giant sequoia trees |work=Los Angeles Times |url=https://www.latimes.com/california/story/2021-10-01/knp-complex-fire-triggers-new-evacuations-and-warning-as-drying-trend-increases-fire-activity |url-status=live |access-date=March 9, 2023 |archive-url=https://web.archive.org/web/20230115130011/https://www.latimes.com/california/story/2021-10-01/knp-complex-fire-triggers-new-evacuations-and-warning-as-drying-trend-increases-fire-activity |archive-date=January 15, 2023}} Approximately 158 homes were threatened between those in Sequoia National Park, in the Lodgepole area, and in the communities of Three Rivers and Hartland.{{Cite news |last=Seidman |first=Lila |others=Contributions by Hayley Smith and Alex Wigglesworth |date=September 28, 2021 |title=Strong winds fanning Windy, KNP Complex fires as they burn through southern Sierra Nevada |work=Los Angeles Times |url=https://www.latimes.com/california/story/2021-09-28/strong-winds-fan-growing-windy-knp-complex-fires |url-status=live |access-date=August 31, 2023 |archive-url=https://web.archive.org/web/20230308031450/https://www.latimes.com/california/story/2021-09-28/strong-winds-fan-growing-windy-knp-complex-fires |archive-date=March 8, 2023}} On September 30, the fire crossed the North Fork of the Kaweah River,{{Cite web |date=October 1, 2021 |title=KNP Complex Update – October 1, 2021 |url=https://inciweb.nwcg.gov/incident-publication/caknp-knp-complex-/knp-complex-update-october-1-2021 |url-status=live |archive-url=https://web.archive.org/web/20230317160751/https://inciweb.nwcg.gov/incident-publication/caknp-knp-complex-/knp-complex-update-october-1-2021 |archive-date=March 17, 2023 |access-date=March 17, 2023 |website=InciWeb}} and entered the lower portion of the Pierce Creek drainage to the north. On October 1, the fire pushed up through Pierce Creek, over the lower parts of the Redwood Mountain ridge, and into Redwood Canyon,{{rp|pages=|page=296}} taking the total burned area to more than {{convert|50000|acres|ha|abbr=on}}.

For the next two days, the fire backed down into Redwood Canyon, burning through Big Springs Grove and making occasional runs up towards Big Baldy (a high granite ridge to the east).{{rp|pages=|page=296}} Redwood Mountain Grove was singled out for concern—park officials knew that its southern section lay on a steep slope and was littered with excess fuel. Firefighters had begun burnout operations in the grove on October 1. Officials also decided to apply an experimental polyacrylamide fire retardant gel to the canopies of the giant sequoias, and some was dropped on trees in Muir Grove.{{Cite news |last=Seidman |first=Lila |date=October 11, 2021 |title='Running out of options': Fight to protect giant sequoias has gotten experimental |work=Los Angeles Times |url=https://www.latimes.com/california/story/2021-10-11/fight-to-protect-giant-sequoias-from-fire-goes-experimental |url-status=live |access-date=April 25, 2023 |archive-url=https://web.archive.org/web/20230308211620/https://www.latimes.com/california/story/2021-10-11/fight-to-protect-giant-sequoias-from-fire-goes-experimental |archive-date=March 8, 2023}} Smoky conditions kept aircraft away from Redwood Mountain Grove, preventing gel drops there, and before long the wildfire outpaced the firefighters' burnout operations.

File:KNP Complex Fire pyrocumulonimbus on 2021-10-04.gif over the southern Sierra Nevada on October 4, as seen by the GOES-17 satellite|alt=A looping gif of satellite imagery shows a massive puff of smoke punch up over the Sierra Nevada before drifting away to the northeast.]]

By October 3, the fire's footprint spanned over {{convert|60000|acres|ha|abbr=on}}.{{Cite web |date=October 3, 2021 |title=KNP Complex Update – October 3, 2021 |url=https://www.nps.gov/seki/learn/news/knp-complex-update-october-3-2021.htm |url-status=live |archive-url=https://web.archive.org/web/20230317142847/https://www.nps.gov/seki/learn/news/knp-complex-update-october-3-2021.htm |archive-date=March 17, 2023 |access-date=March 17, 2023 |website=Sequoia & Kings Canyon National Parks |publisher=National Park Service}} The fire spotted across Mineral King Road, provoking evacuation orders for Sierra King Drive, Hammond, and Oak Grove.{{Cite web |date=October 4, 2021 |title=KNP Complex Update – October 4, 2021 |url=https://www.nps.gov/seki/learn/news/knp-complex-update-october-4-2021.htm |url-status=live |archive-url=https://web.archive.org/web/20230317142708/https://www.nps.gov/seki/learn/news/knp-complex-update-october-4-2021.htm |archive-date=March 17, 2023 |access-date=March 17, 2023 |website=Sequoia & Kings Canyon National Parks |publisher=National Park Service}} That evening, part of the fire still burning near Pierce Meadow surged up the western side of Redwood Mountain. By morning, it had merged with a fire front burning up through Redwood Canyon, and the combined head of the fire burned the central portion of the canyon, scorching the southern part of Redwood Mountain Grove at high severity.{{rp|pages=|page=296}} The fire burned hot in the canyon, putting up {{Convert|40000|ft|m|abbr=out|adj=on}} convective pyrocumulus or pyrocumulonimbus clouds visible from the far side of the Sierra Nevada.{{Cite web |last=Bachmeier |first=Scott |date=October 4, 2021 |title=Pyrocumulonimbus clouds spawned by the KNP Complex wildfire in California |url=https://cimss.ssec.wisc.edu/satellite-blog/archives/42742 |url-status=live |archive-url=https://web.archive.org/web/20220925115907/https://cimss.ssec.wisc.edu/satellite-blog/archives/42742 |archive-date=September 25, 2022 |access-date=August 31, 2023 |website=CIMSS Satellite Blog |publisher=Cooperative Institute for Meteorological Satellite Studies}} In the sequoia grove itself the fire generated winds strong enough to strip bark and foliage from the sequoia trees, and flames likely climbed into the canopies of the sequoias, moving from tree to tree as a crown fire. The fire's run took it across Generals Highway near Stony Creek.{{Cite web |date=October 5, 2021 |title=KNP Complex Update – October 5, 2021 |url=https://www.nps.gov/seki/learn/news/knp-complex-update-october-5-2021.htm |url-status=live |archive-url=https://web.archive.org/web/20230317142159/https://www.nps.gov/seki/learn/news/knp-complex-update-october-5-2021.htm |archive-date=March 17, 2023 |access-date=March 17, 2023 |website=Sequoia & Kings Canyon National Parks |publisher=National Park Service}} The Tulare County Sheriff’s Office issued immediate evacuation orders for Mineral King Road and Mineral King Drive.{{Cite news |last=Smith |first=Hayley |date=October 4, 2021 |title=KNP Complex fire spurs new evacuations as it forms massive pyrocumulus cloud |work=Los Angeles Times |url=https://www.latimes.com/california/story/2021-10-04/knp-complex-fire-evacuations-grow-pyrocumulus-cloud-forms |url-status=live |access-date=November 1, 2023 |archive-url=https://web.archive.org/web/20231031191330/https://www.latimes.com/california/story/2021-10-04/knp-complex-fire-evacuations-grow-pyrocumulus-cloud-forms |archive-date=October 31, 2023}} The fire's intensity subsided upon reaching Big Baldy and parts of the grove that had previously been treated with prescribed fire.{{rp|pages=|page=296}} The Redwood Canyon area growth took the fire's total burned area to just shy of {{convert|80000|acres|ha|abbr=on}} by October 5.

Following the blow-up in Redwood Canyon, shifts in the weather began to enable firefighters to gain the upper hand. On October 8, storms brought rain to the whole of the fire. Some areas received as much as three-tenths of an inch ({{Convert|3/10|in|mm|disp=output only}}) of precipitation.{{Cite web |date=October 9, 2021 |title=KNP Complex Update – October 9, 2021 |url=https://www.nps.gov/seki/learn/news/knp-complex-update-october-9-2021.htm |url-status=live |archive-url=https://web.archive.org/web/20230317135541/https://www.nps.gov/seki/learn/news/knp-complex-update-october-9-2021.htm |archive-date=March 17, 2023 |access-date=March 17, 2023 |website=Sequoia & Kings Canyon National Parks |publisher=National Park Service}} During this same period the total number of personnel assigned to the fire peaked at over 2,000, and it remained around that level for most of the second week of October.{{Cite web |date=October 11, 2021 |title=KNP Complex North and South Zones Update October 11, 2021 |url=https://www.nps.gov/seki/learn/news/knp-complex-north-and-south-zones-update-october-11-2021.htm |url-status=live |archive-url=https://web.archive.org/web/20230317134940/https://www.nps.gov/seki/learn/news/knp-complex-north-and-south-zones-update-october-11-2021.htm |archive-date=March 17, 2023 |access-date=March 17, 2023 |website=Sequoia & Kings Canyon National Parks |publisher=National Park Service}} The favorable weather, particularly on the fire's north end, allowed those crews to achieve 20 percent containment of the fire by October 10.{{Cite web |date=October 10, 2021 |title=KNP Complex North and South Zones Update October 10, 2021 |url=https://www.nps.gov/seki/learn/news/knp-complex-north-and-south-zones-update-october-10-2021.htm |url-status=live |archive-url=https://web.archive.org/web/20230317135212/https://www.nps.gov/seki/learn/news/knp-complex-north-and-south-zones-update-october-10-2021.htm |archive-date=March 17, 2023 |access-date=March 17, 2023 |website=Sequoia & Kings Canyon National Parks |publisher=National Park Service}} Another storm on the night of the 17th brought more than {{Convert|2|in|cm|spell=in}} of snow to the fire area, slowing fire activity further even as hotshot crews built another contingency line beneath the Giant Forest through the snow.{{Cite news |last=Tehee |first=Joshua |date=October 19, 2021 |title=Weekend snowfall slows activity of Sequoia wildfire. A hotshot crew enters Giant Forest |work=The Fresno Bee |url=https://www.fresnobee.com/news/local/article255118022.html |url-status=live |access-date=September 1, 2023 |archive-url=https://web.archive.org/web/20230901135723/https://www.fresnobee.com/news/local/article255118022.html |archive-date=September 1, 2023}}{{Cite web |date=October 19, 2021 |title=KNP Complex Update October 19, 2021 |url=https://www.nps.gov/seki/learn/news/knp-complex-update-october-19-2021.htm |url-status=live |archive-url=https://web.archive.org/web/20211019171926/https://www.nps.gov/seki/learn/news/knp-complex-update-october-19-2021.htm |archive-date=October 19, 2021 |access-date=March 16, 2023 |website=Sequoia & Kings Canyon National Parks |publisher=National Park Service}} Containment rapidly increased to 60 percent by October 21: with a total burned area of {{convert|88307|acres|ha|abbr=out}}, this marked the end of the fire's expansion.{{Cite web |date=October 21, 2021 |title=KNP Complex Update October 21, 2021 |url=https://www.nps.gov/seki/learn/news/knp-complex-update-october-21-2021.htm |url-status=live |archive-url=https://web.archive.org/web/20230316161126/https://www.nps.gov/seki/learn/news/knp-complex-update-october-21-2021.htm |archive-date=March 16, 2023 |access-date=March 16, 2023 |website=Sequoia & Kings Canyon National Parks |publisher=National Park Service}}

On October 24, a significant atmospheric river made landfall in Northern California, delivering several inches of rain across much of the state. Though it weakened as it slid southward,{{Cite news |last=Rodriguez |first=Olga R. |others=Contributions by Janie Har, Christopher Weber, John Antczak, and Brian Melley |date=October 27, 2021 |title='Atmospheric river' drenches drought-stricken California |work=AP News |url=https://apnews.com/article/wildfires-floods-california-los-angeles-droughts-7fabc66dc0cfab55441e1bf25c6c08f9 |url-status=live |access-date=March 17, 2023 |archive-url=https://web.archive.org/web/20221226020634/https://apnews.com/article/wildfires-floods-california-los-angeles-droughts-7fabc66dc0cfab55441e1bf25c6c08f9 |archive-date=December 26, 2022}} {{Convert|2 to 3|in|mm|spell=in}} of rain fell on all parts of the fire and a flash flood watch was issued for the area.{{Cite web |date=October 26, 2021 |title=KNP Complex Update October 26, 2021 |url=https://www.nps.gov/seki/learn/news/knp-complex-update-october-26-2021.htm |url-status=live |archive-url=https://web.archive.org/web/20221222000441/https://www.nps.gov/seki/learn/news/knp-complex-update-october-26-2021.htm |archive-date=December 22, 2022 |access-date=March 17, 2023 |website=Sequoia & Kings Canyon National Parks |publisher=National Park Service}}{{Cite web |date=October 24, 2021 |title=KNP Complex Update October 24, 2021 |url=https://www.nps.gov/seki/learn/news/knp-complex-update-october-24-2021.htm |url-status=live |archive-url=https://web.archive.org/web/20230317181329/https://www.nps.gov/seki/learn/news/knp-complex-update-october-24-2021.htm |archive-date=March 17, 2023 |access-date=March 17, 2023 |website=Sequoia & Kings Canyon National Parks |publisher=National Park Service}} Christy Brigham, chief of resource management and science at Sequoia and Kings Canyon National Parks, declared it a season-ending event. At this point, with the fire largely out, much of the work was focused on repairing the damage from the suppression effort and stabilizing burned areas.{{rp|pages=|page=26|quote="By late October, little heat was left within the fire’s perimeter. Mop up continued in a limited capacity to minimized large sequoia mortality, but suppression efforts shifted from increasing containment to suppression repair and evaluating emergency stabilization needs."}} A week later, control over the incident passed from the interagency incident management team back to the Forest Service and National Park Service.{{Cite web |date=November 1, 2021 |title=KNP Complex Update November 1, 2021 |url=https://www.nps.gov/seki/learn/news/knp-complex-update-november-1-2021.htm |url-status=live |archive-url=https://web.archive.org/web/20220527194613/https://www.nps.gov/seki/learn/news/knp-complex-update-november-1-2021.htm |archive-date=May 27, 2022 |access-date=March 16, 2023 |website=Sequoia & Kings Canyon National Parks |publisher=National Park Service}} The KNP Complex Fire was declared completely contained on December 16, with no further growth expected outside of the existing perimeter.{{Cite web |date=December 17, 2021 |title=KNP Complex Fire Declared 100% Contained |url=https://www.nps.gov/seki/learn/news/knp-complex-fire-declared-100-contained.htm |url-status=live |archive-url=https://web.archive.org/web/20230308031430/https://www.nps.gov/seki/learn/news/knp-complex-fire-declared-100-contained.htm |archive-date=March 8, 2023 |access-date=March 8, 2023 |website=Sequoia & Kings Canyon National Parks |publisher=National Park Service}} The area burned by the fire was calculated at {{convert|88307|acres|ha|abbr=out}},{{Cite web |title=KNP Complex |url=https://www.fire.ca.gov/incidents/2021/9/10/knp-complex/ |url-status=live |archive-url=https://web.archive.org/web/20230307063742/https://www.fire.ca.gov/incidents/2021/9/10/knp-complex/ |archive-date=March 7, 2023 |access-date=March 13, 2023 |website=fire.ca.gov |publisher=California Department of Forestry and Fire Protection}} and the cost of fighting the fire came to $170{{Nbsp}}million.{{rp|pages=|page=9}}

File:KNP_Complex_Fire_aftermath_in_Redwood_Mountain_Grove.jpg

Giant sequoias are typically resistant to wildfires, possessing thick bark and a canopy that grows well above the ground that protects them from smaller fires.{{Cite news |last=Patel |first=Vimal |date=November 20, 2021 |title=Wildfires in California Killed Thousands of Giant Sequoias |language=en-US |work=The New York Times |url=https://www.nytimes.com/2021/11/20/us/california-fires-killed-sequoias.html |url-status=live |access-date=March 8, 2023 |archive-url=https://web.archive.org/web/20230210083517/https://www.nytimes.com/2021/11/20/us/california-fires-killed-sequoias.html |archive-date=February 10, 2023 |issn=0362-4331}} Historically, giant sequoia groves had a fire return interval of approximately 15 years, and so long-lived giant sequoias might see dozens of wildfires throughout their lifetimes. As with the rest of the Sierra Nevada's forests, this ceased with European-American settlement. Sequoia and Kings Canyon parks together contain about {{convert|10000|acres|ha|abbr=on}} of giant sequoia groves, only {{convert|4610|acres|ha|abbr=on}} of which had seen prescribed or managed fire in the 20 years before the KNP Complex Fire. Most of that treated acreage was in the Giant Forest grove alone.{{rp|pages=78–80 |page=|quote="Of the ~10,000 acres of giant sequoia in SEKI, 4,610 acres have received one or more prescribed or managed wildfire in the last 20 years, mostly in Giant Forest."}}

Because of the lack of milder wildfires—leading to fuel build-up—and the intensification of other factors (such as climate change and bark beetles), modern Californian wildfires burn with an increased proportion of moderate to high severity fire effects and such fires have become a "significant threat to the persistence of large sequoias", according to the Park Service's assessment. During the KNP Complex Fire's lifetime, it reached 16 separate giant sequoia groves, and affected some of them severely. The Park Service assessment reported: "Much of the fire’s growth occurred due to backing and flanking, with short uphill runs. However, in some areas terrain, fuels, and winds aligned to drive high intensity crown runs ranging from tens to hundreds of acres."{{rp|pages=|page=24}} Thus, while many groves received low-intensity flanking or backing fire producing effects that varied from "unburned" to "low" severity, several were affected by moderate or high severity runs that killed many mature giant sequoias. Studies have shown an 84 percent average mortality rate in old-growth sequoia groves burned at a high severity, and anecdotal evidence has shown that in multiple fires these areas fail to regenerate.{{rp|pages=79–80|page=|quote="Surveys in old growth groves that burned in three wildfires from 2015 to 2017 identified an average mortality rate of ~84% in high severity areas, which includes delayed mortality three tofive years post fire (Shive et al., in review)."}}

Following the fire's impingement on Castle Creek Grove and Redwood Mountain Grove, park officials wrote on Facebook that they suspected the fire had killed trees in those groves, possibly hundreds of them. Before the fire, Redwood Mountain Grove had been home to 5,509 large giant sequoias, and Castle Creek Grove home to another 419.{{Cite news |last=Paúl |first=María Luisa |date=October 9, 2021 |title=Hundreds of giant sequoias may have been killed in California fires, park officials say |newspaper=The Washington Post |url=https://www.washingtonpost.com/nation/2021/10/09/california-fires-sequoias/ |url-status=live |access-date=March 13, 2023 |archive-url=https://web.archive.org/web/20221202231100/https://www.washingtonpost.com/nation/2021/10/09/california-fires-sequoias/ |archive-date=December 2, 2022}} Officials also wrote that protecting other threatened groves was the current priority and continued fire hazards precluded a complete assessment until later.{{Cite news |last=Seidman |first=Lila |date=October 7, 2021 |title=Hundreds of giant sequoias may have burned to death in KNP Complex, Windy fires |work=Los Angeles Times |url=https://www.latimes.com/california/story/2021-10-07/knp-complex-windy-fires-may-have-killed-hundreds-of-sequoias |url-status=live |access-date=March 13, 2023 |archive-url=https://web.archive.org/web/20230309165746/https://www.latimes.com/california/story/2021-10-07/knp-complex-windy-fires-may-have-killed-hundreds-of-sequoias |archive-date=March 9, 2023}}

On November 19, 2021, the Burned Area Emergency Response (BAER) team assigned to the KNP Complex Fire released their report, which discussed a variety of fire impacts, post-fire hazards, and potential actions for response. Analysis conducted by Nature Conservancy and National Park Service scientists used a combination of fire severity data, satellite imagery, aerial reconnaissance, and ground assessments to estimate possible large giant sequoia mortality from the KNP Complex Fire.{{Cite web |date=November 19, 2021 |title=Giant Sequoia Mortality Estimates Released for the 2021 KNP Complex and Windy Fire |url=https://www.nps.gov/seki/learn/news/giant-sequoia-mortality-estimates-released-for-the-2021-knp-complex-and-windy-fire.htm |url-status=live |archive-url=https://web.archive.org/web/20221002041221/https://www.nps.gov/seki/learn/news/giant-sequoia-mortality-estimates-released-for-the-2021-knp-complex-and-windy-fire.htm |archive-date=October 2, 2022 |access-date=March 16, 2023 |website=Sequoia & Kings Canyon National Parks |publisher=National Park Service}} In total, the National Park Service report estimated that the KNP Complex Fire killed between 1,330 and 2,380 large sequoias, defined as those over {{Convert|4|ft|m|abbr=off|spell=in}} in diameter. That figure includes both the sequoias killed outright and those expected to die in the three to five years following the fire. When combined with the estimated large sequoia mortality of 931–1,257 trees from the Windy Fire, the 2021 California wildfire season saw the potential loss of three to five percent of the global population of large giant sequoias.{{Cite web |last1=Shive |first1=Dr. Kristen |last2=Brigham |first2=Dr. Christy |last3=Caprio |first3=Tony |last4=Hardwick |first4=Paul |title=2021 Fire Season Impacts to Giant Sequoias |url=https://www.nps.gov/articles/000/2021-fire-season-impacts-to-giant-sequoias.htm |url-status=live |archive-url=https://web.archive.org/web/20230209141319/https://www.nps.gov/articles/000/2021-fire-season-impacts-to-giant-sequoias.htm |archive-date=February 9, 2023 |access-date=March 8, 2023 |website=Sequoia & Kings Canyon National Parks |publisher=National Park Service}}{{Cite news |last=Seidman |first=Lila |date=November 19, 2021 |title=Wildfires killed thousands of sequoias in southern Sierra Nevada |work=Los Angeles Times |url=https://www.latimes.com/california/story/2021-11-19/wildfires-kill-thousands-of-sequoias-in-southern-sierra-nevada |url-status=live |access-date=August 19, 2023 |archive-url=https://web.archive.org/web/20230818144049/https://www.latimes.com/california/story/2021-11-19/wildfires-kill-thousands-of-sequoias-in-southern-sierra-nevada |archive-date=August 18, 2023}}{{Cite news |last=Melley |first=Brian |date=November 19, 2021 |title=Wildfires torched up to a fifth of all giant sequoia trees |work=Associated Press |url=https://apnews.com/article/climate-wildfires-science-environment-and-nature-forests-581747bff7abec7b3d090fb8853d8e1a |url-status=live |access-date=August 18, 2023 |archive-url=https://web.archive.org/web/20230602110243/https://apnews.com/article/climate-wildfires-science-environment-and-nature-forests-581747bff7abec7b3d090fb8853d8e1a |archive-date=June 2, 2023}} The National Park Service's assessment highlighted an "alarming trend" given the previous mortality from the Castle Fire portion of the 2020 SQF Complex Fire, which killed an estimated 10–14 percent of large sequoias (or between 7,500 and 10,600 individual trees).{{Cite web |last1=Stephenson |first1=Nathan |last2=Brigham |first2=Christy |date=June 25, 2021 |title=Preliminary Estimates of Sequoia Mortality in the 2020 Castle Fire |url=https://www.nps.gov/articles/000/preliminary-estimates-of-sequoia-mortality-in-the-2020-castle-fire.htm |url-status=live |archive-url=https://web.archive.org/web/20221127074700/https://www.nps.gov/articles/000/preliminary-estimates-of-sequoia-mortality-in-the-2020-castle-fire.htm |archive-date=November 27, 2022 |access-date=March 8, 2023 |website=Sequoia & Kings Canyon National Parks |publisher=National Park Service}} The mortality assessments suggest that in 2020 and 2021, 13–19 percent of the world's large sequoia population was lost in just three large wildfires. Prior to 2020, the total number of large sequoias within the groves of the Sierra Nevada was estimated at 75,580. The total number may have fallen to ~60,000 after the Castle, Windy, and KNP Complex fires.{{Cite news |last=Seidman |first=Lila |date=November 26, 2021 |title='There is nothing alive on that tree': Inside a giant sequoia grove scorched by the KNP Complex fire |work=Los Angeles Times |url=https://www.latimes.com/california/story/2021-11-26/how-the-knp-complex-devastated-one-giant-sequoia-grove |url-status=live |access-date=March 8, 2023 |archive-url=https://web.archive.org/web/20230308031434/https://www.latimes.com/california/story/2021-11-26/how-the-knp-complex-devastated-one-giant-sequoia-grove |archive-date=March 8, 2023}}

On September 23, 2021, Sequoia National Park was the backdrop for Governor Newsom's signature of a $15 billion climate change legislation package that included $1.5 billion for wildfire response and forest resilience. Newsom alluded to the nearby threatened giant sequoias in his remarks on the bill.{{Cite news |last1=Smith |first1=Hayley |last2=Barboza |first2=Tony |date=September 23, 2021 |title=Newsom signs $15-billion package to fight climate change, wildfire and drought |work=Los Angeles Times |url=https://www.latimes.com/california/story/2021-09-23/newsom-signs-15-billion-climate-change-package |url-status=live |access-date=March 8, 2023 |archive-url=https://web.archive.org/web/20230307174257/https://www.latimes.com/california/story/2021-09-23/newsom-signs-15-billion-climate-change-package |archive-date=March 7, 2023}}

In June 2022, the Save Our Sequoias Act was introduced by Democratic member Scott Peters and Republican member Kevin McCarthy (whose district includes the majority of giant sequoia groves) in the House of Representatives. The bill sought to provide $350 million over the course of a decade to codify the Giant Sequoia Lands Coalition (an existing partnership between federal, state, tribal and local land managers), create a reforestation plan for groves destroyed by wildfires, and streamline the environmental review process for thinning and removing vegetation from other groves. Legislators working to draft the bill visited some of the worst-affected groves from the KNP Complex Fire in Sequoia National Park in May, prior to its introduction.{{Cite news |last=Brennan |first=Deborah Sullivan |date=July 13, 2022 |title=Bipartisan House bill aims to rescue California's giant sequoias from wildfires |work=Los Angeles Times |url=https://www.latimes.com/california/story/2022-07-13/bipartisan-house-bill-aims-to-rescue-californias-giant-sequoias-from-wildfires |url-status=live |access-date=March 9, 2023 |archive-url=https://web.archive.org/web/20221221041514/https://www.latimes.com/california/story/2022-07-13/bipartisan-house-bill-aims-to-rescue-californias-giant-sequoias-from-wildfires |archive-date=December 21, 2022}} Despite having 75 co-sponsors in the House, the bill was opposed by 81 environmental groups, including the Sierra Club, the League of Conservation Voters, Greenpeace, the Pacific Crest Trail Association, and Defenders of Wildlife.{{cite letter|first=|last=|author=League of Conservation Voters, Earthjustice, Defenders of Wildlife, Sierra Club, etc|author-link=|recipient=Members of Congress|subject=Sequoias Opposition Letter|language=|date=June 17, 2022|url=https://earthjustice.org/wp-content/uploads/sequoias_opposition_letter_6-21-22.pdf|format=|location=|publisher=Earthjustice|access-date=August 22, 2023|archive-url=https://web.archive.org/web/20230609104908/https://earthjustice.org/wp-content/uploads/sequoias_opposition_letter_6-21-22.pdf|archive-date=June 9, 2023|url-status=live|author-mask=|mode=|id=}}{{Cite web |last=Larabee |first=Mark |date=September 1, 2022 |title=The PCTA opposes the mis-named "Save Our Sequoias Act" |url=https://www.pcta.org/2022/pcta-opposes-sequoias-act-91095/ |url-status=live |archive-url=https://web.archive.org/web/20230103045329/https://www.pcta.org/2022/pcta-opposes-sequoias-act-91095/ |archive-date=January 3, 2023 |access-date=March 9, 2023 |website=Pacific Crest Trail Association}}{{Cite web |last=Botts |first=Lindsey |date=August 2, 2022 |title=Can the Save Our Sequoias Act Match Up to Its Name? |url=https://www.sierraclub.org/sierra/can-save-our-sequoias-act-match-its-name |url-status=live |archive-url=https://web.archive.org/web/20230103045329/https://www.sierraclub.org/sierra/can-save-our-sequoias-act-match-its-name |archive-date=January 3, 2023 |access-date=March 9, 2023 |website=The Sierra Club}} Their joint letter to Congress argued that the bill would "weaken existing environmental law to expedite potentially harmful logging projects that undermine the ecological integrity of sequoia groves and do nothing to protect these trees".{{Cite news |last=Melillo |first=Gianna |date=June 23, 2022 |title=Bipartisan group of lawmakers push bill to save Sequoia trees |work=The Hill |url=https://thehill.com/changing-america/sustainability/environment/3534564-bipartisan-group-of-lawmakers-push-bill-to-save-sequoia-trees/ |url-status=live |access-date=March 9, 2023 |archive-url=https://web.archive.org/web/20220713040113/https://thehill.com/changing-america/sustainability/environment/3534564-bipartisan-group-of-lawmakers-push-bill-to-save-sequoia-trees/ |archive-date=July 13, 2022}} An amended version of the legislation was introduced in the Senate in September 2022 by California senators Dianne Feinstein and Alex Padilla. The act was not passed in either chamber before the end of the 117th Congress in 2023.{{Cite web |title=H.R.8168 - Save Our Sequoias Act: 117th Congress (2021-2022) |url=https://www.congress.gov/bill/117th-congress/house-bill/8168/text?s=1&r=1 |url-status=live |archive-url=https://web.archive.org/web/20230308214411/https://www.congress.gov/bill/117th-congress/house-bill/8168/text?r=1&s=1 |archive-date=March 8, 2023 |access-date=March 9, 2023 |website=Congress.gov}}{{Cite web |title=S.4833 - Save Our Sequoias Act: 117th Congress (2021-2022) |url=https://www.congress.gov/bill/117th-congress/senate-bill/4833 |url-status=live |archive-url=https://web.archive.org/web/20220928221116/https://www.congress.gov/bill/117th-congress/senate-bill/4833 |archive-date=September 28, 2022 |access-date=March 9, 2023 |website=Congress.gov}}

In July 2022, the Forest Service announced that it would begin undertaking "emergency fuels reduction treatments to provide for the long term survival of giant sequoia groves against immediate wildfire threats" by removing vegetation and duff on the surface, thinning areas of the forest, and implementing prescribed burns. The announcement stated that the work would encompass {{convert|13,377|acre|ha|0|abbr=on}} in and around 12 giant sequoia groves in Sequoia and Sierra National Forests, with the intent to complete the work by 2023 at a cost of $15 million in funds from the Infrastructure Investment and Jobs Act and a further $6 million then still unappropriated.{{Cite web |date=July 22, 2022 |title=Forest Service Taking Emergency Action to Protect Giant Sequoias |url=https://www.fs.usda.gov/news/releases/forest-service-taking-emergency-action-protect-giant-sequoias |url-status=live |archive-url=https://web.archive.org/web/20221020174224/https://www.fs.usda.gov/news/releases/forest-service-taking-emergency-action-protect-giant-sequoias |archive-date=October 20, 2022 |access-date=March 14, 2023 |website=Forest Service |publisher=U.S. Department of Agriculture}}{{Cite news |last=Oxenden |first=McKenna |date=July 23, 2022 |title=U.S. Taking Emergency Steps to Protect Sequoias From Wildfires |language=en-US |work=The New York Times |url=https://www.nytimes.com/2022/07/23/us/sequoias-fire-forest-service-emergency-action.html |url-status=live |access-date=March 14, 2023 |archive-url=https://web.archive.org/web/20221105102938/https://www.nytimes.com/2022/07/23/us/sequoias-fire-forest-service-emergency-action.html |archive-date=November 5, 2022 |issn=0362-4331}} In October 2022, the National Park Service separately announced its own emergency actions to protect 11 at-risk and remote giant sequoia groves in Sequoia and Kings Canyon parks by manually thinning vegetation around the trees, burning piles of potential fuels, and using prescribed fire in the thinned areas.{{Cite web |date=October 13, 2022 |title=Sequoia and Kings Canyon National Parks taking emergency action to protect giant sequoias |url=https://www.nps.gov/seki/learn/news/sequoia-and-kings-canyon-national-parks-taking-emergency-action-to-protect-giant-sequoias.htm |url-status=live |archive-url=https://web.archive.org/web/20221013184455/https://www.nps.gov/seki/learn/news/sequoia-and-kings-canyon-national-parks-taking-emergency-action-to-protect-giant-sequoias.htm |archive-date=October 13, 2022 |access-date=March 11, 2023 |website=Sequoia & Kings Canyon National Parks |publisher=National Park Service}} In February 2023, the Park Service began seeking public feedback on replanting sequoia and conifer seedlings in several groves particularly affected by the KNP and SQF Complex fires.{{Cite web |date=February 17, 2023 |title=Sequoia and Kings Canyon National Parks seek public input on planting sequoia seedlings in areas impacted by recent wildfires |url=https://www.nps.gov/seki/learn/news/sequoia-and-kings-canyon-national-parks-seek-public-input-on-planting-sequoia-seedlings-in-areas-impacted-by-recent-wildfires.htm |url-status=live |archive-url=https://web.archive.org/web/20230308031448/https://www.nps.gov/seki/learn/news/sequoia-and-kings-canyon-national-parks-seek-public-input-on-planting-sequoia-seedlings-in-areas-impacted-by-recent-wildfires.htm |archive-date=March 8, 2023 |access-date=March 21, 2023 |website=Sequoia & Kings Canyon National Parks |publisher=National Park Service}}

Below is a summary of the groves that the KNP Complex impacted, the dates those groves burned, the acreage and percentage of each that burned at high severity, and a brief narrative. All information is taken from the National Park Service's report on giant sequoia mortality following the 2021 fire season. Redwood Mountain Grove, Atwell Grove, and Suwanee Grove saw the most acreage burned at high severity.{{rp|pages=|page=101|quote="Redwood Mountain Grove had the most substantial acreage impacted by high severity fire (Figure 10a, 10b) followed by Atwell and Suwanee."}}

On October 7, a falling tree struck four personnel (affiliated with Cal Fire and the California Conservation Corps). All four were transported via helicopter to nearby hospitals with serious injuries, but were listed as stable by that night and released from the hospital the following morning.{{Cite news |last1=Yee |first1=Gregory |last2=Seidman |first2=Lila |date=October 8, 2021 |title=4 firefighters injured by falling tree in KNP Complex burn zone released from hospital |work=Los Angeles Times |url=https://www.latimes.com/california/story/2021-10-07/authorities-responding-to-unspecified-incident-in-knp-complex-fire-area |url-status=live |access-date=March 9, 2023 |archive-url=https://web.archive.org/web/20211119205323/https://www.latimes.com/california/story/2021-10-07/authorities-responding-to-unspecified-incident-in-knp-complex-fire-area |archive-date=November 19, 2021}} On October 11, another firefighter was struck by a falling rock while working in Atwell Grove. They were hospitalized but were expected to recover.{{Cite news |date=October 12, 2021 |title=Firefighter hit by rolling rock while battling KNP Complex Fire |work=KFSN-TV |url=https://abc30.com/knp-complex-fire-firefighter-injury/11113503/ |url-status=live |access-date=March 9, 2023 |archive-url=https://web.archive.org/web/20211019154041/https://abc30.com/knp-complex-fire-firefighter-injury/11113503/ |archive-date=October 19, 2021}}{{Cite news |last=Valenzuela |first=Larry |date=October 11, 2021 |title=Firefighter at Sequoia National Park fire hospitalized after being struck by rolling rock |work=San Luis Obispo Tribune |url=https://www.sanluisobispo.com/news/california/fires/article254938547.html |access-date=March 9, 2023}}

On October 22, Gavin Newsom, the governor of California, declared a state of emergency in Tulare County and multiple other counties affected by the season's fires, allowing residents to access resources through the California Disaster Assistance Act.{{Cite web |date=October 22, 2021 |title=Governor Newsom Issues Emergency Proclamation to Support Counties Recovering from Recent Fires |url=https://www.gov.ca.gov/2021/10/22/governor-newsom-issues-emergency-proclamation-to-support-counties-recovering-from-recent-fires/ |url-status=live |archive-url=https://web.archive.org/web/20230129233301/https://www.gov.ca.gov/2021/10/22/governor-newsom-issues-emergency-proclamation-to-support-counties-recovering-from-recent-fires/ |archive-date=January 29, 2023 |access-date=May 18, 2023 |website=Office of Governor Gavin Newsom}} At least 659 people were displaced by evacuation orders during the fire's active period in early October.{{Cite news |last=Wigglesworth |first=Alex |date=October 2, 2021 |title=Hot, dry weather challenges crews fighting California wildfires |work=Los Angeles Times |url=https://www.latimes.com/california/story/2021-10-02/hot-dry-weather-challenges-crews-fighting-california-wildfires |url-status=live |access-date=November 1, 2023 |archive-url=https://web.archive.org/web/20231031191335/https://www.latimes.com/california/story/2021-10-02/hot-dry-weather-challenges-crews-fighting-california-wildfires |archive-date=October 31, 2023}}

The Giant Forest, which closed in mid-September, reopened first on a limited basis in December 2021 and then fully on March 11, 2022.{{Cite web |date=March 10, 2022 |title=Giant Forest and Wolverton Areas in Sequoia National Park Open 7 Days a Week, Beginning March 11 |url=https://www.nps.gov/seki/learn/news/giant-forest-and-wolverton-areas-open-7-days-a-week-beginning-march-11.htm |url-status=live |archive-url=https://web.archive.org/web/20230311153509/https://www.nps.gov/seki/learn/news/giant-forest-and-wolverton-areas-open-7-days-a-week-beginning-march-11.htm |archive-date=March 11, 2023 |access-date=March 11, 2023 |website=Sequoia & Kings Canyon National Parks |publisher=National Park Service}} The stretch of the Generals Highway between Sequoia and Kings Canyon reopened on March 18, 2022,{{Cite news |last=Parvini |first=Sarah |others=Contributions by Lila Seidman |date=March 19, 2022 |title=Generals Highway between Sequoia and Kings Canyon reopens after KNP Complex fire |work=Los Angeles Times |url=https://www.latimes.com/california/story/2022-03-19/generals-highway-between-sequoia-and-kings-canyon-reopens-after-knp-complex-fire |url-status=live |access-date=March 9, 2023 |archive-url=https://web.archive.org/web/20230308035424/https://www.latimes.com/california/story/2022-03-19/generals-highway-between-sequoia-and-kings-canyon-reopens-after-knp-complex-fire |archive-date=March 8, 2023}} though mudslides re-closed parts of it in the fall of 2022.{{Cite news |date=September 12, 2022 |title=Some access in Sequoia National Forest shut down due to mudslide |work=KFSN-TV |url=https://abc30.com/sequoia-national-park-mudslide-road-closures-generals-highway/12223001/ |url-status=live |access-date=May 18, 2023 |archive-url=https://web.archive.org/web/20230413205534/https://abc30.com/sequoia-national-park-mudslide-road-closures-generals-highway/12223001/ |archive-date=April 13, 2023}} During winter storms in early 2023, fire-weakened hillsides contributed to washouts and damaged culverts, again causing multiple closures along the highway.{{Cite news |last=Sloss |first=Lauren |date=February 8, 2023 |title=What the Winter Storms in California Mean for Travel |language=en-US |work=The New York Times |url=https://www.nytimes.com/2023/02/08/travel/california-winter-storms-travel.html |url-status=live |access-date=March 9, 2023 |archive-url=https://web.archive.org/web/20230307013821/https://www.nytimes.com/2023/02/08/travel/california-winter-storms-travel.html |archive-date=March 7, 2023 |issn=0362-4331}}

The fire destroyed four structures and damaged one, according to Cal Fire.{{Cite report |url=https://34c031f8-c9fd-4018-8c5a-4159cdff6b0d-cdn-endpoint.azureedge.net/-/media/calfire-website/our-impact/fire-statistics/2021_redbook_final.pdf?rev=525959073bbe4bbe816d67624911e4c3&hash=CFD17F879B2CE984AB5BA9FEA4F73A56 |title=2021 Wildfire Activity Statistics |date=2022 |publisher=California Department of Forestry and Fire Protection |access-date=March 14, 2023 |archive-url=https://web.archive.org/web/20230315022902/https://34c031f8-c9fd-4018-8c5a-4159cdff6b0d-cdn-endpoint.azureedge.net/-/media/calfire-website/our-impact/fire-statistics/2021_redbook_final.pdf?rev=525959073bbe4bbe816d67624911e4c3&hash=CFD17F879B2CE984AB5BA9FEA4F73A56 |archive-date=March 15, 2023 |url-status=live}}{{rp|pages=|page=12}} These included a number of historic buildings in Sequoia National Park. The Redwood Mountain Ranger Station (built in 1940), Moro Rock Comfort Station (built in 1934, and Barton's Log/Crose's Cabin, a downed hollow sequoia log converted into a cabin in the 1920s, all burned in the fire.{{rp|pages=178–184|page=}} Redwood Canyon Research Cabin and a private cabin at Oriole Lake were also destroyed.{{rp|pages=|page=24|quote="Destruction of NPS properties (including the Milk Ranch communications site, Moro Rock Comfort Station, Redwood Mountain Ranger Station, and Redwood Canyon Research Cabin) and a private cabin at Oriole Lake."}} The fire destroyed radio transmission towers and other hardware on Eshom Point,{{Cite news |last=Valenzuela |first=Larry |date=November 16, 2021 |title=Radio station off air after generator dies. Fresno operator blames KNP Complex Fire |work=The Fresno Bee |url=https://www.fresnobee.com/news/local/article255824276.html |access-date=March 9, 2023}} damaged park communications equipment on Milk Ranch Peak,{{rp|pages=|page=12|quote="Communication equipment at the site that is critical to park operations was burned in the fire and is non-functional"}} and damaged an electrical distribution line belonging to Southern California Edison.{{rp|pages=|page=24|quote="Damage to Southern California Edison 12 kV distribution line."}}

No campgrounds, picnic areas, or administrative buildings in either park were directly impacted by the fire,{{rp|pages=61, 135|page=}} but other park infrastructure was affected. For example, {{convert|62.3|mi|km|0|abbr=out}} of trail within the fire's perimeter suffered varying degrees of damage. Sequoia National Park contained {{convert|44.2|mi|km|0|abbr=out}} of the total and Kings Canyon National Park the remaining {{convert|18.1|mi|km|0|abbr=out}}. {{convert|9|mi|km|0|abbr=out|spell=In}}, representing 20 percent of Sequoia National Park's burned trails, and {{convert|7.4|mi|km|0|abbr=out}}, representing 40 percent of the burned trails in Kings Canyon National Park, were within moderate or high burn severity areas. An additional {{convert|6.1|mi|km|0|abbr=out}} of trails were used as containment lines along the fire's perimeter, and did not wholly burn.{{rp|pages=149–153|page=}} Other impacts included damage to signage throughout the park, including road reflectors, speed limit signs, and posts,{{rp|pages=161–168|page=}} and nearly 20,000 potentially hazardous burned trees along roads in the parks.{{rp|pages=59–72|page=}}

In addition to giant sequoia mortality, the Burned Area Emergency Response (BAER) team evaluated a host of other environmental impacts from the fire. The KNP Complex Fire burned critical habitat for the Pacific fisher, a small carnivorous mammal whose southern Sierra Nevada population is listed as endangered under the Endangered Species Act of 1973. One of the primary reasons for the species' listing is the loss and fragmentation of its habitat due to high-severity wildfire.{{rp|pages=210–213|page=}} More than {{convert|27000|acre|ha|0|abbr=on}} of proposed critical fisher habitat burned in the fire, 58 percent of it at moderate to high severities. More than {{convert|60000|acre|ha|0|abbr=on}} of spotted owl habitat (much of it overlapping with fisher habitat) also burned, 46 percent of it at moderate to high severities.{{rp|pages=216–219|page=}}

The BAER team also evaluated soil burn severity using satellite imagery and field observations for calibration. A qualitative metric based on the amount of remaining surface material, soil stability, and soil hydrophobicity, soil burn severity influences post-fire runoff and debris flow issues. The KNP Complex Fire's overall footprint was calculated to contain 12.4 percent unburned, 48.8 percent low, and 38.8 percent moderate-to-high soil burn severity.{{rp|pages=|page=30}}File:Windy Fire smoke satellite view.jpg's GOES-17 satellite]]The KNP Complex Fire and the Windy Fire's smoke output created hazardous air quality conditions in the San Joaquin Valley, including the city of Fresno, between late September and early October.{{Cite news |last=Hawkins |first=Stephen |date=October 1, 2021 |title=Smoke, bad air forcing schools to cancel football games |work=KMPH-TV |url=https://kmph.com/news/local/smoke-bad-air-forcing-schools-to-cancel-football-games |url-status=live |access-date=March 12, 2023 |archive-url=https://web.archive.org/web/20220901164911/https://kmph.com/news/local/smoke-bad-air-forcing-schools-to-cancel-football-games |archive-date=September 1, 2022}}{{Cite web |date=September 30, 2021 |title=Air Quality Alert Due to Wildfire Smoke: KNP Complex and Windy Fire Send Smoke Into the Valley |url=https://inciweb.nwcg.gov/incident-publication/casqf-windy-fire/air-quality-alert-due-to-wildfire-smoke |url-status=live |archive-url=https://web.archive.org/web/20230321155902/https://inciweb.nwcg.gov/incident-publication/casqf-windy-fire/air-quality-alert-due-to-wildfire-smoke |archive-date=March 21, 2023 |access-date=March 21, 2023 |website=InciWeb |publisher=San Joaquin Valley Air Pollution Control District}}{{Cite news |last=Smith |first=Hayley |date=September 22, 2021 |title=Wildfires approach more giant sequoias and worsen air quality across Central California |work=Los Angeles Times |url=https://www.latimes.com/california/story/2021-09-22/wildfires-approach-more-giant-sequoias-and-worsen-air-quality-across-central-california |url-status=live |access-date=March 21, 2023 |archive-url=https://web.archive.org/web/20230308215751/https://www.latimes.com/california/story/2021-09-22/wildfires-approach-more-giant-sequoias-and-worsen-air-quality-across-central-california |archive-date=March 8, 2023}} On September 27, the air quality index in Three Rivers near the KNP Complex Fire soared to 350 (the second-highest reading in the country that day after Kernville, which was inundated by smoke from the Windy Fire) and the South Coast Air Quality Management District issued a special air quality advisory for parts of the San Gabriel and San Bernardino mountains.{{Cite news |last=Seidman |first=Lila |date=September 27, 2021 |title=Heavy wildfire smoke prompts air advisory in Southern California |work=Los Angeles Times |url=https://www.latimes.com/california/story/2021-09-27/fire-smoke-triggers-air-quality-advisory-for-southern-california-mountains |access-date=March 12, 2023 |archive-url=https://web.archive.org/web/20221109041314/https://www.latimes.com/california/story/2021-09-27/fire-smoke-triggers-air-quality-advisory-for-southern-california-mountains |archive-date=November 9, 2022}} When winds pushed smoke further south into the Los Angeles basin, many people called 911, and firefighters responded to multiple reports of drift smoke in the Angeles National Forest as skies turned hazy shades of brown and orange.{{Cite news |last=Wigglesworth |first=Alex |date=September 23, 2021 |title=Smoky L.A. skies are from wildfires to the north, officials say |work=Los Angeles Times |url=https://www.latimes.com/california/story/2021-09-23/smoky-l-a-skies-are-from-wildfires-to-the-north-officials-say |url-status=live |access-date=March 12, 2023 |archive-url=https://web.archive.org/web/20220929074938/https://www.latimes.com/california/story/2021-09-23/smoky-l-a-skies-are-from-wildfires-to-the-north-officials-say |archive-date=September 29, 2022}}

The table below shows how the fire grew in size and in containment during September and October 2021. Acreage reflects, where possible, the figure reported in the daily morning update following overnight aerial infrared mapping of the fire. The graph runs from September 10, the day the fires were discovered, until October 21, the last day where fire growth was reported (though the fire was not declared completely contained until nearly two months later).

• Glossary of wildfire terms
• Rough Fire (2015) – Killed giant sequoias in General Grant Grove
• Pier Fire (2017) – Killed giant sequoias in Black Mountain Grove
• Railroad Fire (2017) – Killed giant sequoias in Nelder Grove
• Washburn Fire (2022) – Threatened giant sequoias in Mariposa Grove

{{notelist}}

{{Reflist}}

• [https://www.nps.gov/seki/learn/nature/knp-complex-fire.htm National Park Service (SEKI): KNP Complex Fire]
• [http://inciweb.nwcg.gov/incident-information/caknp-knp-complex InciWeb: KNP Complex Incident Information]
• [https://wildfiretoday.com/tag/knp-complex/ Wildfire Today, Tag: KNP Complex]

{{California wildfires}}

Category:2021 California wildfires

Category:September 2021 in the United States

Category:October 2021 in the United States

Category:Wildfires in Tulare County, California

Category:Sequoia National Park

Category:Kings Canyon National Park