Document Type

Article

Publication Date

7-3-2025

Department

Michigan Tech Research Institute

Abstract

Background: Wildfires and consequent postfire hazards, specifically runoff-generated debris flows, are a major threat to California communities. Aim: To help prefire planning efforts across California, we identified areas that are most susceptible to postfire debris flows before fire occurs. Methods: We developed a calibration method for an established model that relates existing vegetation type to fire severity, a critical input to the US Geological Survey’s postfire debris-flow likelihood model. We calibrated the model for eight regions with data from 81 wildfires that occurred in 2020 and 2021 in California. Key results: We predicted debris-flow likelihood, volume, and combined hazard classification, and created statewide maps that use simulated fire frequency and rainfall data to predict the probability that a basin will experience a wildfire and subsequent debris flow. Conclusions: We suggest that the model predictions are useful for identifying areas that pose the greatest risk of postfire debris-flow hazard for a simplified wildfire scenario. Implications: Although actual patterns of wildfire severity may vary from our simulated products, we show that applying a consistent methodology for all of California is useful for identifying areas that are likely to pose the greatest postfire hazards, which should help focus prefire mitigation efforts.

Publisher's Statement

© 2025 The Author(s) (or their employer(s)). Published by CSIRO Publishing on behalf of IAWF. Publisher’s version of record: https://doi.org/10.1071/WF24225

Publication Title

International Journal of Wildland Fire

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