USDA Forest Service

North Central Research Station

[Image]: Color contour map of the continental United States showing Lower Atmospheric Severity Index spacer

Haines Index


[Photograph]: Don Haines reveling in his retirement.

The Lower Atmosphere Severity Index (often called the Haines Index after retired RWU-4401 meteorologist Donald Haines) describes the above-surface air mass as it affects large and/or erratic wildland fires.  LASI is most important when the surface fire danger is high; if LASI is also high, it can lead to explosive conditions.

The LASI should be considered along with a surface Fire Danger Index for maximum effectiveness.  Obviously, if surface fuels are green and wet, that condition would be more important than the state of the above-surface atmosphere.

The LASI is based on a two parameter model determined by the environmental lapse rate of a layer of air, coupled with its moisture content.  The height of the layer of air depends on general surface elevation above sea level.  The layer selected varies from region to region.

Time of computation of LASI is 0000 UTC.  The results are presented in a four-category adjective classification for severity, from Very Low to High.

In 1998, the USDA Forest Service North Central Research Station and the University of Wisconsin, Madison Department of Atmospheric and Oceanic Sciences began making forecasts of the Haines Index for fire weather available over the world wide web.  Through this cooperative agreement, 0-hour, 24-hour, and 48-hour forecasts of the Haines Index are available every day.

Since late 1998, these images have been archived and analyzed.  Using the 0-hour images, which reflect direct observations of the atmosphere without any type of forecast, we have created maps of the average Haines Index for each month available.  These maps can be used to note seasonal patterns in the Haines Index and how conducive the atmosphere is to fostering large wildfires.

January, 1999, Average Haines Index January, 2000, Average Haines Index January, 2001, Average Haines Index spacer July, 1999, Average Haines Index July, 2000, Average Haines Index
Jan 1999 Jan 2000 Jan 2001   Jul 1999 Jul 2000
February, 1999, Average Haines Index February, 2000, Average Haines Index February, 2001, Average Haines Index August, 1999, Average Haines Index August, 2000, Average Haines Index
Feb 1999 Feb 2000 Feb 2001 Aug 1999 Aug 2000
March, 1999, Average Haines Index March, 2000, Average Haines Index March, 2001, Average Haines Index September, 1999, Average Haines Index September, 2000, Average Haines Index
Mar 1999 Mar 2000 Mar 2001 Sep 1999 Sep 2000
April, 1999, Average Haines Index April, 2000, Average Haines Index April, 2001, Average Haines Index October, 1999, Average Haines Index October, 2000, Average Haines Index
Apr 1999 Apr 2000 Apr 2001 Oct 1999 Oct 2000
May, 1999, Average Haines Index May, 2000, Average Haines Index May, 2001, Average Haines Index November, 1999, Average Haines Index November, 2000, Average Haines Index
May 1999 May 2000 May 2001 Nov 1999 Nov 2000
June, 1999, Average Haines Index June, 2000, Average Haines Index December, 1999, Average Haines Index December, 2000, Average Haines Index
Jun 1999 Jun 2000 Dec 1999 Dec 2000
Note:  Each month's average depends on a different number of days.  The dates used for a specific month are listed in the date link below the map thumbnail.  Also, it is important to note that average values can be fractions, while the Index for a given day is always a whole number.


Publications can be obtained from your local library, the appropriate journal, or the authors, if supplies remain.

  • Regional analysis of Haines' LASI.  Potter B. 1995. Fire Management Notes. 55(3):30.
  • The Haines index and Idaho wildfire growth.  Werth P, Ochoa R. 1990. Fire Management Notes. 51(4):9-13.
  • A lower-atmosphere severity index for wildland fires.  Haines D. 1988. National Weather Digest. 13(2):23-27.

For more information:

USDA Forest Service - North Central Research Station
Last Modified: January 26, 2005