Great Basin rangeland fire probability

Preliminary products
Updated June 15, 2021

This page is no longer updated. Please visit the primary page for updates.

Where are large fires most likely to occur throughout the year given an ignition?

These maps represent the relative probability of large (> 1,000 acres) rangeland fire given an ignition. Probabilities are for the entire year or fire season. Maps should be used alongside other fire risk or prediction services. Probabilities are calculated using RAP biomass, RAP cover, and various climate/drought indices. Maps are updated every 16 days through early June.

Great Basin rangeland fire
probability

Previous 2021 probabilities
May 25, 2021
May 09, 2021
April 23, 2021
April 07, 2021

How does this year compare to the past?

There is a clear relationship between the area-wide average fire probability across the Great Basin in the month of May and the total area burned that year (see figure below). 2021 is shown as a yellow dot (which moves every 16-days based on the probability map) and represents a coarse prediction of the total area burned for 2021. This allows us to compare how the coming fire season might relate to past years in terms of total area burned. This prediction, however, entails considerable uncertainty. Besides fuels, the severity of the fire season depends on variables such as fire weather, ignitions, and fire suppression resource availability that cannot be predicted months in advance.

Great Basin rangeland fire
area

Previous 2021 area predictions
May 25, 2021
May 09, 2021
April 23, 2021
April 07, 2021

What do past years look like?

The figure below shows the total area burned each year (large wildfires >1,000 acres) in the Great Basin. Bars are color-coded to display how much of that area was in each probability category by May of that year. The overwhelming majority of wildfire occurred in areas with probabilities >0.5 (warm colors). Areas with lower probabilities (cold colors) burned much less.

Great Basin rangeland fire
area-probability

Probabilities of past years and the fires that occurred (depicted by purple polygons) can be viewed in the video below.