Seasonal influence on post-fire debris flow likelihood after the 2020 Lake Fire
- 1University of New Mexico (Albuquerque, United States of America)
- 2California State University, Northridge (Northridge, United States of America)
- 3GEOMAR Helmholtz Centre for Ocean Research Kiel (Kiel, Germany)
Abstract
The increasing severity of wildfires in Western North America is widely hypothesized to lead to an increase in the likelihood of post-fire debris flows (PFDF), specifically those triggered by high-intensity rain. PFDF likelihoods are highest in the first year and tend to decrease over time. However, it is not well understood how seasonal variation affects PFDF initiation in the years following a fire. Here, we investigated how different physical parameters influence seasonal PFDF likelihood, informed by four years of field and satellite observations from the 2020 Lake Fire in Southern California. We found that unsaturated hydraulic conductivity was an order of magnitude greater during the dry season than during the wet season, significantly reducing the PFDF likelihood. Our simulations show that vegetation cover has less of an impact on PFDF likelihood than hydraulic conductivity or grain size. This study helps clarify the relative importance of hydraulic conductivity, grain size, and vegetation on PFDF as these parameters vary seasonally and evolve over four years after the fire. Our results suggest that seasonal variation plays a major role in determining PFDF likelihood and therefore, climatic and seasonal patterns need to be considered in future field and modeling studies.
Versions
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BibTeX
@article{chong2026seasonal,
title = {{Seasonal influence on post-fire debris flow likelihood after the 2020 Lake Fire}},
author = {Jeng-Hann Chong and Adit Ghosh and Brandon T. Page and Greg Jesmok and Denise V. Berg and Marlene Lopez and Deepshikha Upadhyay and David J. Stone and Scott C. Hauswirth and Eric O. Lindsey and Louis A. Scuderi},
journal = {Natural Hazards and Earth System Sciences},
year = {2026},
month = oct,
doi = {10.5194/nhess-26-4723-2026},
url = {https://nhess.copernicus.org/articles/26/4723/2026/},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Seasonal influence on post-fire debris flow likelihood after the 2020 Lake Fire
AU - Jeng-Hann Chong
AU - Adit Ghosh
AU - Brandon T. Page
AU - Greg Jesmok
AU - Denise V. Berg
AU - Marlene Lopez
AU - Deepshikha Upadhyay
AU - David J. Stone
AU - Scott C. Hauswirth
AU - Eric O. Lindsey
AU - Louis A. Scuderi
PY - 2026
DA - 2026/10/02
JO - Natural Hazards and Earth System Sciences
DO - 10.5194/nhess-26-4723-2026
UR - https://nhess.copernicus.org/articles/26/4723/2026/
AB - The increasing severity of wildfires in Western North America is widely hypothesized to lead to an increase in the likelihood of post-fire debris flows (PFDF), specifically those triggered by high-intensity rain. PFDF likelihoods are highest in the first year and tend to decrease over time. However, it is not well understood how seasonal variation affects PFDF initiation in the years following a fire. Here, we investigated how different physical parameters influence seasonal PFDF likelihood, informed by four years of field and satellite observations from the 2020 Lake Fire in Southern California. We found that unsaturated hydraulic conductivity was an order of magnitude greater during the dry season than during the wet season, significantly reducing the PFDF likelihood. Our simulations show that vegetation cover has less of an impact on PFDF likelihood than hydraulic conductivity or grain size. This study helps clarify the relative importance of hydraulic conductivity, grain size, and vegetation on PFDF as these parameters vary seasonally and evolve over four years after the fire. Our results suggest that seasonal variation plays a major role in determining PFDF likelihood and therefore, climatic and seasonal patterns need to be considered in future field and modeling studies.
SN - 1684-9981
ER -