Supplemental Appropriations for Disaster Recovery Activities

Assessment of Landslide and Debris-Flow Impacts from California Wildfires

Wildfire increases the susceptibility of steep slopes to landslides and debris flows. A tragic recent example occurred in Montecito, California, where heavy rainfall on the Thomas fire triggered debris flows that killed 23 people and damaged or destroyed over 400 homes.

Drone footage of the 2018 Carr Fire at Whiskeytown National Recreation area in Northern California in October 2018, captured by drone pilot and USGS WERC ecologist Chase Freeman.

Chase Freeman, USGS Western Ecological Research Center

(Public domain.)



  • The USGS will use data from the Thomas and Carr wildfires to deliver tools for predicting post-fire debris-flow inundation and downstream impacts to inform mitigation and evacuation plans.
  • Data from wildfires will be used to refine USGS models for hazard assessments, increasing their utility for hazard management in temperate environments and post-fire recovery, as well as to improve rainfall criteria for debris-flow warnings issued by the National Weather Service.








Additional Resources:

McGuire, L.A., Rengers, F.K., Oakley, N., Kean, J.W., Staley, D.M., Tang, H., de Orla-Barile, M., and Youberg, A.M., 2021, Time Since Burning and Rainfall Characteristics Impact Post-Fire Debris-Flow Initiation and Magnitude: Environmental and Engineering Geoscience, v. 27, no. 1, p. 43-56.

Lancaster, J.T., Swanson, B.J., Lukashov, S.G., Oakley, N.S., Lee, J.B., Spangler, E.R., Hernandez, J.L., Olson, B.P.E., DeFrisco, M.J., Lindsay, D.N., Schwartz, Y.J., McCrea, S.E., Roffers, P.D., and Tran, C.M., 2021, Observations and Analyses of the 9 January 2018 Debris-Flow Disaster, Santa Barbara County, California: Environmental and Engineering Geoscience, v. 27, no. 1, p. 3-27.

Sidder, A. (2021), The wildfire one-two: First the burn, then the landslides, Eos, 102, 22 June 2021.


Jonathan Godt

Program Coordinator
Landslide Hazards
Phone: 303-273-8626