Predicting Wildfire in the Western U.S. Under a Changing Climate

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A new publication examines the relationships between climate, hydrology, and wildfire – offering insight for improving the predictive power of wildfire models.

Huge blaze engulfing trees

Huge wildfire

(Public domain.)

Although a complex process, wildfire modeling can have huge benefits for natural resource managers and communities who are looking to predict, prepare for, and reduce the damage caused by wildfires. For this reason, scientists are continually striving to build on and improve the quality of their wildfire projections.

A recently published paper from Donald McKenzie, U.S. Forest Service, and Jeremy Littell, Alaska Climate Science Center, offers a step in this direction. Currently, almost all statistical models and simulations predict that climate change will increase the area burned by wildfires. However, the researchers challenge the assumptions traditionally made by these models, pointing out why this conclusion may not apply to all areas of the western United States.

For 56 small ecological regions across the West, McKenzie and Littell used historical data to examine how climate and hydrology corresponded with the annual area burned by wildfire. One of the assumptions that has guided past modeling efforts is that “hotter and drier equals more fire.” The researchers found that while this assumption held in some areas (generally forests), it was not necessarily true in non-forested and desert regions. In these areas, additional variables such as the amount of vegetation and the previous year’s climate played a critical role in determining the total area affected by wildfire. Thus, wildfire predictions could be improved by incorporating these factors.

Moreover, McKenzie and Littell point out, the relationships between climate, water balance, and fire in an area will change over time as the climate changes. This fact is typically not accounted for by models, but is an important consideration when trying to forecast future wildfire. The researchers note this as an additional future direction for model improvement. 

The full paper, Climate change and the eco-hydrology of fire: Will area burned increase in a warming western USA?, is available in Ecological Applications.