White River Ash

{{Short description|1,200-year-old ash deposit in North America}}

The White River Ash is a 1,500-year-old tephra deposit found in the southern part of the Yukon Territory, Canada and eastern Alaska.{{Cite journal |last=Lerbekmo |first=J. F. |last2=Campbell |first2=F. A. |date=February 1969 |title=Distribution, composition, and source of the White River Ash, Yukon Territory |url=https://cdnsciencepub.com/doi/10.1139/e69-011 |journal=Canadian Journal of Earth Sciences |volume=6 |issue=1 |pages=109–116 |doi=10.1139/e69-011 |issn=0008-4077|url-access=subscription }} The deposit is bilobate,{{Cite journal |last=Lerbekmo |first=J. F. |last2=Campbell |first2=F. A. |date=February 1969 |title=Distribution, composition, and source of the White River Ash, Yukon Territory |url=https://cdnsciencepub.com/doi/10.1139/e69-011 |journal=Canadian Journal of Earth Sciences |volume=6 |issue=1 |pages=109–116 |doi=10.1139/e69-011 |issn=0008-4077|url-access=subscription }} formed by two large (VEI 6) explosive eruptions from the stratovolcano of Mount Churchill that occurred around 850 AD and blanketed {{convert|340000|km2|sqmi|abbr=on}}.

{{cite web

| url=http://cgrg.geog.uvic.ca/abstracts/WestEvidenceRhyodacitic.html

| archiveurl = https://web.archive.org/web/20090408052616/http://cgrg.geog.uvic.ca/abstracts/WestEvidenceRhyodacitic.html

| archivedate= 2009-04-08

| title = Evidence for winter eruption of the White River Ash (eastern lobe), Yukon Territory

| author1 = West, K.D. | author2 = Donaldson, J.D.

| work = CGRG Bibliography of Canadian Geomorphology | publisher = The Canadian Geomorphology Research Group | year = 2000

| accessdate = 2007-07-09}} While originally believed to only exist within North America, recent observations (2014) have found crypto-tephra from the eruption across northern Europe.