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Central California Coast Debris Flows - January 2021

July 22, 2022
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An atmospheric river (AR) moved into California late on the evening of January 26, 2021, bringing intermittent heavy rainfall that resulted in flooding, debris flows, and heavy snowfall at high elevations. This story map collection uses interactive maps, photographs, and rainfall data to tell the story of debris flows in four 2020 burn areas along the central California Coast during the atmospheric river event.  Events highlighted in this collection occurred in the River, CZU Lightning Complex, Dolan, and Carmel burn areas.  

tan pickup truck surrounded by mud and rocks up to the top of the door
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On Sunday, August 16, 2020 at approximately 3:00 PM PST, the River wildfire ignited in Monterey County, California, just west of the Salinas River Valley. The fire burned 20 square kilometers prior to containment on September 4, 2020. Debris-flow deposits at the Chualar and Limekiln sites within the River Burn area were observed on Wednesday, January 27, 2021, and were likely triggered by rainfall events in the early morning hours of January 27, 2021.

Related

The spatial distribution of debris flows in relation to observed rainfall anomalies: Insights from the Dolan Fire, California

A range of hydrologic responses can be observed in steep, recently burned terrain, which makes predicting the spatial distribution of large debris flows challenging. Studies from rainfall-induced landslides in unburned areas show evidence of hydroclimatic tuning of landslide triggering, such that the spatial distribution of events is best predicted by the observed rainfall anomaly relative to clim
Authors
David B. Cavagnaro, Scott W. McCoy, Matthew A. Thomas, Jaime Kostelnik, Donald N. Lindsay
By
Natural Hazards Mission Area, Landslide Hazards Program, Geologic Hazards Science Center

Postfire hydrologic response along the central California (USA) coast: Insights for the emergency assessment of postfire debris-flow hazards

The steep, tectonically active terrain along the Central California (USA) coast is well known to produce deadly and destructive debris flows. However, the extent to which fire affects debris-flow susceptibility in this region is an open question. We documented the occurrence of postfire debris floods and flows following the landfall of a storm that delivered intense rainfall across multiple burn a
Authors
Matthew A. Thomas, Jason W. Kean, Scott W. McCoy, Donald N. Lindsay, Jaime Kostelnik, David B. Cavagnaro, Francis K. Rengers, Amy E. East, Jonathan Schwartz, Douglas P. Smith, Brian D. Collins
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Natural Hazards Mission Area, Landslide Hazards Program, Geologic Hazards Science Center, Geology, Minerals, Energy, and Geophysics Science Center, Pacific Coastal and Marine Science Center, Supplemental Appropriations for Disaster Recovery Activities

The USGS partners with other federal, state, and local agencies to collect observations in recently burned areas following storm events.  These agencies provide valuable data that supports the USGS Landslide Hazards Program research effort.  

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California Geological Survey (CGS)

NOAA National Weather Service (NWS)

U.S. Forest Service (USFS)

Related

The spatial distribution of debris flows in relation to observed rainfall anomalies: Insights from the Dolan Fire, California

A range of hydrologic responses can be observed in steep, recently burned terrain, which makes predicting the spatial distribution of large debris flows challenging. Studies from rainfall-induced landslides in unburned areas show evidence of hydroclimatic tuning of landslide triggering, such that the spatial distribution of events is best predicted by the observed rainfall anomaly relative to clim
Authors
David B. Cavagnaro, Scott W. McCoy, Matthew A. Thomas, Jaime Kostelnik, Donald N. Lindsay
By
Natural Hazards Mission Area, Landslide Hazards Program, Geologic Hazards Science Center

Postfire hydrologic response along the central California (USA) coast: Insights for the emergency assessment of postfire debris-flow hazards

The steep, tectonically active terrain along the Central California (USA) coast is well known to produce deadly and destructive debris flows. However, the extent to which fire affects debris-flow susceptibility in this region is an open question. We documented the occurrence of postfire debris floods and flows following the landfall of a storm that delivered intense rainfall across multiple burn a
Authors
Matthew A. Thomas, Jason W. Kean, Scott W. McCoy, Donald N. Lindsay, Jaime Kostelnik, David B. Cavagnaro, Francis K. Rengers, Amy E. East, Jonathan Schwartz, Douglas P. Smith, Brian D. Collins
By
Natural Hazards Mission Area, Landslide Hazards Program, Geologic Hazards Science Center, Geology, Minerals, Energy, and Geophysics Science Center, Pacific Coastal and Marine Science Center, Supplemental Appropriations for Disaster Recovery Activities

The USGS partners with other federal, state, and local agencies to collect observations in recently burned areas following storm events.  These agencies provide valuable data that supports the USGS Landslide Hazards Program research effort.  

CAL FIRE

California Geological Survey (CGS)

NOAA National Weather Service (NWS)

U.S. Forest Service (USFS)

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