16-6 Post-fire Watershed Emergency Response Team (WERT) efforts for the 2024 Airport Fire, Orange and Riverside Counties, California

Session: Wildland Fire: An Agent of Geomorphic, Ecologic, and Societal Change

Presenting Author:

W. Paul Burgess

Authors:

Burgess, W. Paul¹, Sabbeth, Leah², Callahan, Kevin³, Kang, Meerea⁴, Brown Jr., Deshawn A.⁵, Cavagnaro, David B.⁶, Lindsay, Don⁷

Abstract:

The Airport Fire ignited on September 9, 2024, in Trabuco Canyon, Orange County, and burned until it was 100% contained on October 6, 2024. The fire spread into the Santa Ana Mountains, burning eastwards into western Riverside County. The Airport Fire burned 23,526 acres, destroyed 160 structures, and damaged an additional 34 structures. There were two civilian injuries, 20 firefighter injuries, and no fatalities. Given past post-fire runoff response to fires in the region (e.g. 2020 Bond Fire), proximity of the burn scar to developed areas, and forecast of rain showers, the California Geological Survey (CGS) supported the California Department of Forestry and Fire Prevention (CAL FIRE) by deploying a Watershed Emergency Response Team (WERT) to perform a rapid evaluation of post-fire geologic and hydrologic hazards to life safety and property - collectively known as “Values at Risk” (VARs) - on private lands affected by the fire. Primary concerns for burned watersheds are the increased potential for damaging sediment and debris flood flows, increased potential for debris flow occurrence, rockfall from steep slopes, and hillslope erosion resulting in excessive sedimentation due to storm runoff for several years following the fire. Partnership with county and municipal agencies, as well as maintaining communications with locally impacted communities and citizens facilitated effective identification of Emergency Protection Measures (EPMs) critical for citizens living in hazard areas within and downstream of the burned area. Here, we present significant WERT findings and discuss how ongoing monitoring efforts during stressing rainfall events contribute crucial data to calibrate fire-specific debris-flow producing rainfall thresholds and improve regional forecasting of future potential debris flow events. We additionally highlight the importance of consistent hazard communication prior to and during stressing rainfall events to promote interagency situational awareness for emergency preparedness and response, ensuring public safety within and adjacent to a recently burned landscape.

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-10083

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