Haines Index

{{Short description|Estimation of the risk of wildfire}}

Haines Index (also known as the Lower Atmosphere Severity Index) is a weather index developed by meteorologist Donald Haines in 1988 that measures the potential for dry, unstable air to contribute to the development of large or erratic wildland fires.{{cite web|title=Haines Index |url=http://www.ncrs.fs.fed.us/4401/focus/haines/ |publisher=USA Forest Service |access-date=16 April 2014 |url-status=dead |archive-url=https://web.archive.org/web/20140416182854/http://www.ncrs.fs.fed.us/4401/focus/haines/ |archive-date=April 16, 2014 }} The index is derived from the stability (temperature difference between different levels of the atmosphere) and moisture content (dew point depression) of the lower atmosphere. These data may be acquired with a radiosonde or simulated by a numerical weather prediction model. The index is calculated over three ranges of atmospheric pressure: low elevation (950-850 millibars (mb)), mid elevation (850-700 mb), and high elevation (700-500 mb).[http://www.spc.noaa.gov/exper/firecomp/INFO/hainesinfo.html Noaa]

A Haines Index of 6 means a high potential for an existing fire to become large or exhibit erratic fire behavior, 5 means medium potential, 4 means low potential, and anything less than 4 means very low potential.{{cite journal|last1=Winkler|first1=Julie A.|last2=Potter|first2=Brian E.|last3=Wilhelm|first3=Dwight F.|last4=Shadbolt|first4=Ryan P.|last5=Piromsopa|first5=Krerk|last6=Bian|first6=Xindi|title=Climatological and statistical characteristics of the Haines Index for North America|journal=International Journal of Wildland Fire|date=2007|volume=16|issue=2|pages=139–152|doi=10.1071/WF06086|citeseerx=10.1.1.486.1768}}{{Cite web |url=https://graphical.weather.gov/definitions/defineHaines.html |title=Haines index definition |access-date=2018-05-20 |archive-date=2024-01-25 |archive-url=https://web.archive.org/web/20240125005402/https://graphical.weather.gov/definitions/defineHaines.html |url-status=dead }}