This webinar draws on more than a century of fire records, from 1910 to 2021, combined with climate and weather data to better understand what shapes fire behavior across different ecoregions.

The presentation introduces a framework that distinguishes between immediate drivers, such as fuel conditions and ignition sources, and underlying factors like long-term climate patterns and land use. Findings show that wildfire drivers vary widely across California. In northern forested regions, fire activity is closely linked to fuel aridity tied to climate conditions, along with the accumulation of woody fuels influenced by fire suppression. In contrast, lower elevation grassland and foothill areas tend to experience more burning following wetter winter and spring seasons, when increased plant growth creates abundant fine fuels.

The webinar will also examine how ignition sources differ across landscapes. Lightning events can occur in concentrated bursts, igniting multiple fires at once and stretching firefighting capacity. In more developed areas, human-caused ignitions are more common, with infrastructure such as powerlines playing a growing role as populations expand.

Understanding these regional differences is essential for developing effective management strategies. This session will provide insights into how fire regimes may respond to future climate conditions and why tailored approaches are needed across ecosystems.

Causal Analysis of Fire Regime Drivers

Date: Friday, May 29, 2026
Time: 2:00–3:00 PM ET | 11:00 AM–12:00 PM PT
Speaker: Jon E. Keeley, Senior Scientist, USGS Western Ecological Research Center
 

This webinar is free and open to natural resource professionals, scientists, and anyone interested in understanding wildfire science and management.