Post Fire Debris Flow Quick Links
This page brings together information on post fire debris flow risks as well as debris flow hazard and soil burn severity assessments for individual California wildfires from the past 5 years.
Key Points about Post-Fire Debris Flows
Normally, vegetation absorbs rainfall, reducing runoff. However, wildfires leave the ground charred, barren, and unable to absorb water, creating conditions ripe for flash flooding and mudflow.
Flood risk remains significantly higher until vegetation is restored—up to 5 years after a wildfire.
While some floods develop over time, flash floods—particularly common after wildfires—can occur within minutes after the onset of a rainstorm. Even areas that are not traditionally flood-prone are at risk, due to changes to the landscape caused by fire.
Source: National Weather Service Post Wild Fire Flash Flood and Debris Flow Guide
General Resources About Debris Flows After Fires
USGS Emergency Assessment of Post-Fire Debris-Flow Hazards – This database provides maps that depict the likelihood and potential volume of debris flows as they exit the mountain front in response to a design storm having a 15-minute peak rainfall intensity of 24 mm/h in the immediate aftermath of the fire. The models are designed to assess the potential for debris flow in the locations where debris flows initiate (i.e., where they form and get larger). The maps are not subsequently updated in following years and do not identify debris-flow runout paths, areas of inundation, or assess potential damage. Links to each of the California fires, starting with 2023 fires, are including in the county information below. FAQs about USGS assessment
California Department of Conservation’s Recent Burned Watershed Hazard Assessments – California Watershed Emergency Response Teams (WERTs) help communities prepare after wildfire by rapidly documenting and communicating post-fire risks to life and property posed by debris flow, flood, and rock fall hazards.
USDA Natural Resources Conservation Service’s After the Fire Resources –
Post Fire Restoration Dos and Don’ts
Preparing for at Least Two Winters Following Wildfire
Drought Influences on Post- Wildfire Flooding and Debris Flow Hazard – The hazards posed by post-fire flooding and debris flows in burned landscapes depends on burn severity, underlying geology and topography, and vegetation recovery following the fire. Because vegetation recovery depends on weather and climate conditions, drought may play an important role in controlling the likelihood and magnitude of debris-flow hazards during the recovery process.
UCLA Institute of Transportation Studies – Vulnerability of California Roadways to Post-Wildfire Debris Flows – Published in 2020, this paper examines current and future conditions, considering climate change scenarios, and how they affect fire risk and precipitation. Results show how post-fire debris flow risks change from today into the future.
California – Flood After Fire Toolkit: A Resource for Technical Specialists to Assess Flood and Debris Flow Risk After a Wildfire (technical document) – This toolkit provides a collection of tools, methods, and other resources – grouped into chronologically distinct periods of a flood after fire response timeline – to help assess the risks associated with flooding and debris flow after a fire.
Debris Flow Hazards Webinar Recording
On December 7, 2020 the California Resilience Alliance hosted a Winter Weather Outlook & Debris Flow Hazards Webinar. Don Lindsay from the California Geological Society presented on post-fire effects including erosion-induced debris flows, post-fire models currently being applied to predict hazard, and monitoring program to test models and improve ability to predict post-fire hazards. The video picks up at the Debris Flow Hazards portion of the combined webinar.
Debris Flow Hazard Assessment Maps & County Specific Resources
Wildfires that crossed county lines are included under each of the counties where a burn scar was left. The impacts of a debris flow may cross into adjacent counties. If your locations of interest are near county lines, it is recommended that you also look at the neighboring county to see if there is potential risk from nearby burn scars.
USGS Hazard Assessments: depict the likelihood of debris-flow generation and estimates of flow magnitude in locations where debris flows initiate. The models do not predict downstream impacts, potential debris-flow runout paths, and the areal extent of debris-flow or flood inundation. Hazard assessments are not updated in subsequent years.
USGS Hazard Assessment Viewer offers several assessment layers (all are in response to the design rainstorm with a peak 15-minute rainfall intensity of 24mm/hr / 0.94 inches/hr):
- Likelihood / Probability Estimates (probability of a debris flow as a percent range)
- Volume Estimates (predicted volume in cubic meters)
- Combined Hazard Estimates (likelihood + volume)
Navigating the Assessment Viewer
Using the layers menu in the upper right corner of the map, users can change the visible layers. Changes have to be made individually for each year. If the assessment layers do not appear on the map for a specific fire, you may need to zoom in more. There are separate layers for probability (likelihood) estimates, volume estimates, and combined likelihood and volume estimates.
Along the top bar are option for filtering fires by name, year, and state. The filtered list appears in the left side bar.
When clicking on a fire an information box appears that provides links to downloadable Goedatabase and Shapefiles, along with a link to a pdf map.
California Large Fire Burn Scar Map (last 5 years)
Links to debris flow hazard and soil burn severity assessment information for wildfires by county:
Note: Debris flow hazard and soil burn severity assessments are not conducted for all wildfires.
Alameda County
SCU Lightning Complex (2020): Combined basin hazard (likelihood + volume) per USGS assessment is low to moderate.
Alpine County
Caldor Fire (2021): Combined basin hazard (likelihood + volume) per USGS assessment is mostly moderate with a few areas of high (segment probability pdf map). US Forest Service Burned Area Emergency Response (BAER) team also created an Assessment Report Summary.
Tamarack Fire (2021): Combined basin hazard (likelihood + volume) per USGS assessment is mostly moderate with a few areas of high (segment probability pdf map).
Slink Fire (2020): Combined basin hazard (likelihood + volume) per USGS assessment is mostly moderate (segment probability pdf map).
Amador County
Caldor Fire (2021): Combined basin hazard (likelihood + volume) per USGS assessment is mostly moderate with a few areas of high (segment probability pdf map). US Forest Service Burned Area Emergency Response (BAER) team also created an Assessment Report Summary.
Butte County
Park Fire (2024): Combined basin hazard (likelihood + volume) per the USGS assessment is moderate to high.
Dixie Fire (2021): Combined basin hazard (likelihood + volume) per the USGS assessment is mostly moderate to high with some areas of low (Due to its size the Dixie fire was assessed in 3 phases: phase 1 segment probability pdf map (366,000 acres in the area south and west of Chester, Lake Almanor, and Taylorsville), phase 2 segment probability pdf map (403,500 acres to both the north and east and south and east of Chester and Lake Almanor), and phase 3 segment probability pdf map (the remaining 207,977 acres including the northwest side and southeast portion)). The USGS has also created story map that provides details about the Dixie fire, the level of debris-flow hazard immediately following the fire, and how burned watersheds responded to rainfall in the first year following the wildfire.
North Complex (2020): Combined basin hazard (likelihood + volume) per USGS assessment is moderate to high (segment probability pdf map).
Colusa County
LNU Lightning Complex – Hennessey Fire (2020): Combined basin hazard (likelihood + volume) per USGS assessment is mostly low to moderate with a larger area of high south of Lake Berryessa (segment probability pdf map). Cal OES and the California Department of Conservation have released a Watershed Emergency Response Team Evaluation for the Hennessey Fire.
Del Norte County
Smith River Complex (2023): Combined basin hazard (likelihood + volume) per USGS assessment is moderate to high. The US Forest Service Burned Area Emergency Response (BAER) assessment team estimated that approximately51% of the Smith River Complex was either unburned/very low or low SBS, 34% was moderate and 15% was high SBS. Generally burned areas with high SBS are prone to post-fire impacts (soil burn severity maps).
SRF Lightning Complex (2023): Combined basin hazard (likelihood + volume) per USGS assessment is low to moderate. The US Forest Service Burned Area Emergency Response (BAER) assessment team estimated that approximately 69% of the SRF Lightning Complex was either unburned/very low or low SBS, 27% was moderate and 4% was high SBS. Generally burned areas with moderate and high SBS are prone to post-fire impacts (soil burn severity map). The US Forest Service also released a Post-Fire BAER Assessment Summary.
Slater Fire (2020): Combined basin hazard (likelihood + volume) per USGS assessment is high (segment probability pdf map).
El Dorado County
Mosquito Fire (2022): Combined basin hazard (likelihood + volume) per USGS assessment is low to moderate with some areas of high (segment probability pdf map).
Caldor Fire (2021): Combined basin hazard (likelihood + volume) per USGS assessment is mostly moderate with a few areas of high (segment probability pdf map). US Forest Service Burned Area Emergency Response (BAER) team also created an Assessment Report Summary.
Fresno County
Basin Fire (2024): Combined basin hazard (likelihood + volume) per USGS assessment is moderate to high.
Creek Fire (2020): Combined basin hazard (likelihood + volume) per USGS assessment is moderate to high (segment probability pdf map).
Glenn County
August Complex (2020): Combined basin hazard (likelihood + volume) per USGS assessment is mostly moderate with some areas of high (segment probability pdf map). US Forest Service Burned Area Emergency Response (BAER) assessment for the August Complex-South fire area found approximately 52% of the 521,256 acres analyzed by the BAER team is either unburned/very low (9%) or low (43%) soil burn severity, while 44% sustained a moderate soil burn severity, and only 4% burned at high soil burn severity. For the August Complex-North fire area, approximately 61% of the 551,493 acres analyzed by the BAER team is either unburned/very low (32%) or low (29%) soil burn severity, while 31% sustained a moderate soil burn severity, and only 8% burned at high soil burn severity.
Humboldt County
Boise Fire (2024): Combined basin hazard (likelihood + volume) per USGS assessment is mostly moderate with one area of high.
Hill Fire (2024): Combined basin hazard (likelihood + volume) per USGS assessment is moderate to high.
SRF Lightning Complex – Lone Pine Fire (2023): Combined basin hazard (likelihood + volume) per USGS assessment is low to moderate.
SRF Lightning Complex (2023): Combined basin hazard (likelihood + volume) per USGS assessment is low to moderate. The US Forest Service Burned Area Emergency Response (BAER) assessment team estimated that approximately 69% of the SRF Lightning Complex was either unburned/very low or low SBS, 27% was moderate and 4% was high SBS. Generally burned areas with moderate and high SBS are prone to post-fire impacts (soil burn severity map).
Six Rivers Lightning Complex (2022): Combined basin hazard (likelihood + volume) per USGS assessment mostly low to moderate with one larger area of high (segment probability pdf map).
Knob Fire (2021): Combined basin hazard (likelihood + volume) per USGS assessment is low to moderate (segment probability pdf map).
Red Salmon Complex (2020): Combined basin hazard (likelihood + volume) per USGS assessment is mostly moderate with some areas of high (segment probability pdf map).
Kern County
Borel Fire (2024): Combined basin hazard (likelihood + volume) per USGS assessment is mostly moderate with some areas of high.
French Fire (2021): Combined basin hazard (likelihood + volume) per USGS assessment is mostly moderate with an area of high (segment probability pdf map).
Lake County
August Complex (2020): Combined basin hazard (likelihood + volume) per USGS assessment is mostly moderate with some areas of high (segment probability pdf map). US Forest Service Burned Area Emergency Response (BAER) assessment for the August Complex-South fire area found approximately 52% of the 521,256 acres analyzed by the BAER team is either unburned/very low (9%) or low (43%) soil burn severity, while 44% sustained a moderate soil burn severity, and only 4% burned at high soil burn severity. For the August Complex-North fire area, approximately 61% of the 551,493 acres analyzed by the BAER team is either unburned/very low (32%) or low (29%) soil burn severity, while 31% sustained a moderate soil burn severity, and only 8% burned at high soil burn severity.
LNU Lightning Complex – Hennessey Fire (2020): Combined basin hazard (likelihood + volume) per USGS assessment is mostly low to moderate with a larger area of high south of Lake Berryessa (segment probability pdf map). Cal OES and the California Department of Conservation have released a Watershed Emergency Response Team Evaluation for the Hennessey Fire.
Lassen County
Beckwourth Complex (2021): Combined basin hazard (likelihood + volume) per USGS assessment is mostly moderate with one area of high (segment probability pdf map).
Dixie Fire (2021): Combined basin hazard (likelihood + volume) per the USGS assessment is mostly moderate to high with some areas of low (Due to its size the Dixie fire was assessed in 3 phases: phase 1 segment probability pdf map (366,000 acres in the area south and west of Chester, Lake Almanor, and Taylorsville), phase 2 segment probability pdf map (403,500 acres to both the north and east and south and east of Chester and Lake Almanor), and phase 3 segment probability pdf map (the remaining 207,977 acres including the northwest side and southeast portion)). The USGS has also created story map that provides details about the Dixie fire, the level of debris-flow hazard immediately following the fire, and how burned watersheds responded to rainfall in the first year following the wildfire.
Loyalton Fire (2020): Combined basin hazard (likelihood + volume) per USGS assessment is low to moderate (segment probability pdf map).
Sheep Fire (2020): Combined basin hazard (likelihood + volume) per USGS assessment is moderate with some areas low (segment probability pdf map).
Los Angeles County
Department of Public Works – Debris and Mudflow Potential Forecast
Bridge Fire (2024): Combined basin hazard (likelihood + volume) per USGS assessment is mostly high. US Forest Service Burned Area Emergency Response (BAER) assessment found soil burn severity for the burned area is High (7%), Moderate (51%), Low (31%), and Very Low/Unburned (11%). (Soil Burn Severity Map)
Post Fire (2024): Combined basin hazard (likelihood + volume) per USGS assessment is moderate.
Route Fire (2022): Combined basin hazard (likelihood + volume) per USGS assessment is mostly moderate (segment probability pdf map).
Bobcat Fire (2020): Combined basin hazard (likelihood + volume) per USGS assessment is moderate to high, with the high being mostly in the southern portion (segment probability pdf map). US Forest Service Burned Area Emergency Response (BAER) team also completed an assessment report to support funding requests.
Lake Fire (2020): Combined basin hazard (likelihood + volume) per USGS assessment is moderate to high (segment probability pdf map).
Ranch 2 Fire (2020): Combined basin hazard (likelihood + volume) per USGS assessment is moderate to high, with most of the high hazard area on the southern more populated side (segment probability pdf map).
Madera County
Washburn Fire (2022): Combined basin hazard (likelihood + volume) per USGS assessment is low to moderate (segment probability pdf map).
Creek Fire (2020): Combined basin hazard (likelihood + volume) per USGS assessment is moderate to high (segment probability pdf map).
Marin County
Woodward Fire (2020): Combined basin hazard (likelihood + volume) per USGS assessment is mostly low to moderate with one area of high (segment probability pdf map).
Mariposa County
French Fire (2024): Combined basin hazard (likelihood + volume) per USGS assessment is moderate.
Oak Fire (2022): Combined basin hazard (likelihood + volume) per USGS assessment is mostly moderate with one larger area of high hazard (segment probability pdf map).
Washburn Fire (2022): Combined basin hazard (likelihood + volume) per USGS assessment is low to moderate (segment probability pdf map).
Mendocino County
August Complex (2020): Combined basin hazard (likelihood + volume) per USGS assessment is mostly moderate with some areas of high (segment probability pdf map). US Forest Service Burned Area Emergency Response (BAER) assessment for the August Complex-South fire area found approximately 52% of the 521,256 acres analyzed by the BAER team is either unburned/very low (9%) or low (43%) soil burn severity, while 44% sustained a moderate soil burn severity, and only 4% burned at high soil burn severity. For the August Complex-North fire area, approximately 61% of the 551,493 acres analyzed by the BAER team is either unburned/very low (32%) or low (29%) soil burn severity, while 31% sustained a moderate soil burn severity, and only 8% burned at high soil burn severity.
Merced County
SCU Lightning Complex (2020): Combined basin hazard (likelihood + volume) per USGS assessment is low to moderate.
Mono County
Slink Fire (2020): Combined basin hazard (likelihood + volume) per USGS assessment is mostly moderate (segment probability pdf map).
Monterey County
Monterey County Post-Fire Watershed Values at Risk Map
Colorado Fire (2022): Combined basin hazard (likelihood + volume) per USGS assessment is low to moderate (segment probability pdf map).
Willow Fire (2021): Combined basin hazard (likelihood + volume) per USGS assessment is high (segment probability pdf map).
Carmel Fire (2020): Combined basin hazard (likelihood + volume) per USGS assessment is mostly moderate (segment probability pdf map). Cal OES and the California Department of Conservation have released a Watershed Emergency Response Team Evaluation for the River and Carmel Fires.
Dolan Fire (2020): Combined basin hazard (likelihood + volume) per USGS assessment is moderate to high (segment probability pdf map).
River Fire (2020): Combined basin hazard (likelihood + volume) per USGS assessment is mostly low to moderate with two area of high hazard (segment probability pdf map). Cal OES and the California Department of Conservation have released a Watershed Emergency Response Team Evaluation for the River and Carmel Fires.
Napa County
Napa County’s GIS WERT Report Post-Fire Map
Glass Fire (2020): Combined basin hazard (likelihood + volume) per USGS assessment is mostly low to moderate with some areas of high (segment probability pdf map). Cal OES and the California Department of Conservation have released a Watershed Emergency Response Team Evaluation for the Glass Fire.
LNU Lightning Complex – Hennessey Fire (2020): Combined basin hazard (likelihood + volume) per USGS assessment is mostly low to moderate with a larger area of high south of Lake Berryessa (segment probability pdf map). Cal OES and the California Department of Conservation have released a Watershed Emergency Response Team Evaluation for the Hennessey Fire.
Nevada County
River Fire (2021): Combined basin hazard (likelihood + volume) per USGS assessment is low to moderate (segment probability pdf map).
Orange County
Orange County Public Work’s Homeowners’ Guide for Flood, Debris, and Erosion Control after Fires
Airport Fire (2024): Combined basin hazard (likelihood + volume) per USGS assessment is moderate to high.
Jim Fire (2022): Combined basin hazard (likelihood + volume) per USGS assessment is moderate (segment probability pdf map).
Blue Ridge Fire (2020): Combined basin hazard (likelihood + volume) per USGS assessment is low to moderate (segment probability pdf map).
Bond Fire (2020): Combined basin hazard (likelihood + volume) per USGS assessment is low to moderate (segment probability pdf map). USGS Storymap on January & March 2021 Bond Fire Debris Flows.
Silverado Fire (2020): Combined basin hazard (likelihood + volume) per USGS assessment is low to moderate (segment probability pdf map).
Placer County
Mosquito Fire (2022): Combined basin hazard (likelihood + volume) per USGS assessment is low to moderate with some areas of high (segment probability pdf map).
River Fire (2021): Combined basin hazard (likelihood + volume) per USGS assessment is low to moderate (segment probability pdf map).
Plumas County
Beckwourth Complex (2021): Combined basin hazard (likelihood + volume) per USGS assessment is mostly moderate with one area of high (segment probability pdf map).
Dixie Fire (2021): Combined basin hazard (likelihood + volume) per the USGS assessment is mostly moderate to high with some areas of low (Due to its size the Dixie fire was assessed in 3 phases: phase 1 segment probability pdf map (366,000 acres in the area south and west of Chester, Lake Almanor, and Taylorsville), phase 2 segment probability pdf map (403,500 acres to both the north and east and south and east of Chester and Lake Almanor), and phase 3 segment probability pdf map (the remaining 207,977 acres including the northwest side and southeast portion)). The USGS has also created story map that provides details about the Dixie fire, the level of debris-flow hazard immediately following the fire, and how burned watersheds responded to rainfall in the first year following the wildfire.
Loyalton Fire (2020): Combined basin hazard (likelihood + volume) per USGS assessment is low to moderate (segment probability pdf map).
North Complex (2020): Combined basin hazard (likelihood + volume) per USGS assessment is moderate to high (segment probability pdf map).
North Complex – Claremont Fire (2020): Combined basin hazard (likelihood + volume) per USGS assessment is mostly moderate to high with some perimeter areas being low (segment probability pdf map).
Sheep Fire (2020): Combined basin hazard (likelihood + volume) per USGS assessment is moderate with some areas low (segment probability pdf map).
Riverside County
Airport Fire (2024): Combined basin hazard (likelihood + volume) per USGS assessment is moderate to high. US Forest Service Burned Area Emergency Response (BAER) assessment found soil burn severity for the burned area is High (3%), Moderate (77%), Low or Very Low/Unburned (approximately 20%). (Soil Burn Severity Map)
Nixon Fire (2024): Combined basin hazard (likelihood + volume) per USGS assessment is moderate.
Bonny Fire (2023): Combined basin hazard (likelihood + volume) per USGS assessment is low to moderate. The California Watershed Emergency Response Team (WERT) Evaluation’s Burned Area Reflectance Classification (BARC) indicated approximately 76 acres (3%) of unburned/very low soil burn severity, 451 acres (20%) of low soil burn severity, 1,625 acres (70%) of moderate soil burn severity, and 171 acres (7%) of high soil burn severity within the fire perimeter. A copy of the WERT report can be requested for electronic download from the California Department of Conservation.
Highland Fire (2023): Combined basin hazard (likelihood + volume) per USGS assessment is low.
Fairview Fire (2022): Combined basin hazard (likelihood + volume) per USGS assessment is low to moderate (segment probability pdf map).
Jim Fire (2022): Combined basin hazard (likelihood + volume) per USGS assessment is moderate (segment probability pdf map).
Blue Ridge Fire (2020): Combined basin hazard (likelihood + volume) per USGS assessment is low to moderate (segment probability pdf map).
Snow Fire (2020): Combined basin hazard (likelihood + volume) per USGS assessment is low to moderate (segment probability pdf map).
Apple and El Dorado Fires (2020): Combined basin hazard (likelihood + volume) per USGS assessment is moderate to high (segment probability pdf map).
San Bernardino County
Bridge Fire (2024): Combined basin hazard (likelihood + volume) per USGS assessment is mostly high. US Forest Service Burned Area Emergency Response (BAER) assessment found soil burn severity for the burned area is High (7%), Moderate (51%), Low (31%), and Very Low/Unburned (11%). (Soil Burn Severity Map)
Line Fire (2024): Combined basin hazard (likelihood + volume) per USGS assessment is moderate with many area of high. US Forest Service Burned Area Emergency Response (BAER) assessment found soil burn severity for the burned area is High (21%), Moderate (23%), Low (50%), and Very Low/Unburned (7%). (Soil Burn Severity Map)
Vista Fire (2024): Combined basin hazard (likelihood + volume) per USGS assessment is mostly moderate with some areas of high.
Sheep Fire (2022): Combined basin hazard (likelihood + volume) per USGS assessment is mostly low with an area of moderate (segment probability pdf map).
Apple and El Dorado Fires (2020): Combined basin hazard (likelihood + volume) per USGS assessment is moderate to high (segment probability pdf map).
Blue Ridge Fire (2020): Combined basin hazard (likelihood + volume) per USGS assessment is low to moderate (segment probability pdf map).
San Diego County
Coyote Fire (2023): Combined basin hazard (likelihood + volume) per USGS assessment is low.
Border 32 Fire (2022): Combined basin hazard (likelihood + volume) per USGS assessment is low to moderate (segment probability pdf map).
Border 13 Fire (2022): Combined basin hazard (likelihood + volume) per USGS assessment is low (segment probability pdf map).
Valley Fire (2020): Combined basin hazard (likelihood + volume) per USGS assessment is low to moderate (segment probability pdf map).
San Joaquin County
SCU Lightning Complex (2020): Combined basin hazard (likelihood + volume) per USGS assessment is low to moderate.
San Luis Obispo County
Lizzie Fire (2023): Combined basin hazard (likelihood + volume) per USGS assessment is low. The California Watershed Emergency Response Team (WERT) Evaluation’s soil burn severity map indicates approximately 29 acres (23%) of unburned/very low soil burn severity, 95 acres (76.6%) of low soil burn severity, and less than 1 acre (0.4%) of moderate soil burn severity within the fire perimeter. A copy of the WERT report can be requested for electronic download from the California Department of Conservation.
San Mateo County
CZU Lightning Complex (2020): Combined basin hazard (likelihood + volume) per USGS assessment is moderate to high with some areas of low (segment probability pdf map).
Santa Barbara County
Lake Fire (2024): Combined basin hazard (likelihood + volume) per USGS assessment is moderate to high.
Alisal Fire (2021): Combined basin hazard (likelihood + volume) per USGS assessment is mostly moderate with one area of high (segment probability pdf map). US Forest Service Burned Area Emergency Response (BAER) Soil Burn Severity Maps.
Scorpion Fire (2020): Combined basin hazard (likelihood + volume) per USGS assessment is low (segment probability pdf map). This fire is in Channel Island National Park on one of the islands off the coast of California.
Cave Fire (2019): Combined basin hazard (likelihood + volume) per USGS assessment is moderate with some of the southern portions as low (segment probability pdf map).
Santa Clara County
SCU Lightning Complex (2020): Combined basin hazard (likelihood + volume) per USGS assessment is low to moderate.
Santa Cruz County
County Resource Conservation District – Post Fire Recovery
CZU Lightning Complex (2020): Combined basin hazard (likelihood + volume) per USGS assessment is moderate to high with some areas of low (segment probability pdf map). A Memorandum “Landslide and Debris Flow Hazard Conditions Now Threatening the San Lorenzo Valley, Caused by the CZU Wildfire” to the District Board of Directors and public also provides addition information about the post-fire risks in the area. The California Department of Conservation also conducted a Boulder Creek Post-WERT Study for this fire. Santa Cruz County has also released a 2020 CZU Lightning Complex Fire Post-Fire Watershed Recovery Guide.
Shasta County
Shoe Fire (2024): Combined basin hazard (likelihood + volume) per USGS assessment is moderate to high.
Dixie Fire (2021): Combined basin hazard (likelihood + volume) per the USGS assessment is mostly moderate to high with some areas of low (Due to its size the Dixie fire was assessed in 3 phases: phase 1 segment probability pdf map (366,000 acres in the area south and west of Chester, Lake Almanor, and Taylorsville), phase 2 segment probability pdf map (403,500 acres to both the north and east and south and east of Chester and Lake Almanor), and phase 3 segment probability pdf map (the remaining 207,977 acres including the northwest side and southeast portion)). The USGS has also created story map that provides details about the Dixie fire, the level of debris-flow hazard immediately following the fire, and how burned watersheds responded to rainfall in the first year following the wildfire.
McFarland Fire (2021): Combined basin hazard (likelihood + volume) per USGS assessment is moderate to high (segment probability pdf map).
Salt Fire (2021): Combined basin hazard (likelihood + volume) per USGS assessment is mostly moderate with some areas of high (segment probability pdf map).
Sierra County
Loyalton Fire (2020): Combined basin hazard (likelihood + volume) per USGS assessment is low to moderate (segment probability pdf map).
Siskiyou County
Shelly Fire (2024): Combined basin hazard (likelihood + volume) per USGS assessment is moderate to high. US Forest Service Burned Area Emergency Response (BAER) assessment found soil burn severity for the burned area is High (16%), Moderate (29%), Low (40%), and Very Low/Unburned (15%). (Soil Burn Severity Map) The Forest SErvice also created a Vegetation Mortality Map.
SRF Lightning Complex (2023): The US Forest Service Burned Area Emergency Response (BAER) assessment team estimated that approximately 69% of the SRF Lightning Complex was either unburned/very low or low SBS, 27% was moderate and 4% was high SBS. Generally burned areas with moderate and high SBS are prone to post-fire impacts (soil burn severity map).
Happy Camp Complex (2023): Combined basin hazard (likelihood + volume) for the Elliot and Fish fires per USGS assessment is low to moderate. US Forest Service Burned Area Emergency Response (BAER) team estimated that approximately 80% of the Happy Camp Complex was either unburned/very low or low soil burn severity (SBS), 18% was moderate and 2% was high SBS (soil burn severity maps and burn area report).
McKinney Fire (2022): Combined basin hazard (likelihood + volume) per USGS assessment is moderate to high (segment probability pdf map).
Mountain Fire (2022): Combined basin hazard (likelihood + volume) per USGS assessment is moderate to high (segment probability pdf map).
Yeti Fire (2022): Combined basin hazard (likelihood + volume) per USGS assessment is moderate to high (segment probability pdf map).
Antelope Fire (2021): Combined basin hazard (likelihood + volume) per USGS assessment is low to moderate with an area of high (segment probability pdf map).
Lava Fire (2021): Combined basin hazard (likelihood + volume) per USGS assessment is moderate (segment probability pdf map).
McCash Fire (2021): Combined basin hazard (likelihood + volume) per USGS assessment is moderate to high (segment probability pdf map).
River Complex (2021): Combined basin hazard (likelihood + volume) per USGS assessment is moderate to high (segment probability pdf map).
Tennant Fire (2021): Combined basin hazard (likelihood + volume) per USGS assessment is low to moderate (segment probability pdf map).
Devil Fire (2020): Combined basin hazard (likelihood + volume) per USGS assessment is moderate (segment probability pdf map).
Red Salmon Complex (2020): Combined basin hazard (likelihood + volume) per USGS assessment is mostly moderate with some areas of high (segment probability pdf map).
Slater Fire (2020): Combined basin hazard (likelihood + volume) per USGS assessment is high (segment probability pdf map).
Solano County
LNU Lightning Complex – Hennessey Fire (2020): Combined basin hazard (likelihood + volume) per USGS assessment is mostly low to moderate with a larger area of high south of Lake Berryessa (segment probability pdf map). Cal OES and the California Department of Conservation have released a Watershed Emergency Response Team Evaluation for the Hennessey Fire.
Sonoma County
County of Sonoma Post-Fire Hazard Assessment Map
Sonoma County – Preparing for Rain After Wildfires
How to Prepare Burned Properties for Rain after the Glass Fire
City of Santa Rosa – Preparing for Rain After Wildfires
Glass Fire (2020): Combined basin hazard (likelihood + volume) per USGS assessment is mostly low to moderate with some areas of high (segment probability pdf map). Cal OES and the California Department of Conservation have released a Watershed Emergency Response Team Evaluation for the Glass Fire.
LNU Lightning Complex – Meyers Fire (2020): Combined basin hazard (likelihood + volume) per USGS assessment is mostly low to moderate with one area high (segment probability pdf map).
LNU Lightning Complex – Walbridge Fire (2020): Combined basin hazard (likelihood + volume) per USGS assessment is mostly low to moderate with two larger areas of high (segment probability pdf map).
Stanislaus County
SCU Lightning Complex (2020): Combined basin hazard (likelihood + volume) per USGS assessment is low to moderate.
Tehama County
Park Fire (2024): Combined basin hazard (likelihood + volume) per the USGS assessment is moderate to high. US Forest Service Burned Area Emergency Response (BAER) assessment found soil burn severity for the burned area is High (7%), Moderate (36%), Low (53%), and Very Low/Unburned (4%). (Soil Burn Severity Map) Soil burn severity was mapped for all developed areas, both urban and rural, within the affected landscape.
Dixie Fire (2021): Combined basin hazard (likelihood + volume) per the USGS assessment is mostly moderate to high with some areas of low (Due to its size the Dixie fire was assessed in 3 phases: phase 1 segment probability pdf map (366,000 acres in the area south and west of Chester, Lake Almanor, and Taylorsville), phase 2 segment probability pdf map (403,500 acres to both the north and east and south and east of Chester and Lake Almanor), and phase 3 segment probability pdf map (the remaining 207,977 acres including the northwest side and southeast portion)). The USGS has also created story map that provides details about the Dixie fire, the level of debris-flow hazard immediately following the fire, and how burned watersheds responded to rainfall in the first year following the wildfire.
McFarland Fire (2021): Combined basin hazard (likelihood + volume) per USGS assessment is moderate to high (segment probability pdf map).
August Complex (2020): Combined basin hazard (likelihood + volume) per USGS assessment is mostly moderate with some areas of high (segment probability pdf map). US Forest Service Burned Area Emergency Response (BAER) assessment for the August Complex-South fire area found approximately 52% of the 521,256 acres analyzed by the BAER team is either unburned/very low (9%) or low (43%) soil burn severity, while 44% sustained a moderate soil burn severity, and only 4% burned at high soil burn severity. For the August Complex-North fire area, approximately 61% of the 551,493 acres analyzed by the BAER team is either unburned/very low (32%) or low (29%) soil burn severity, while 31% sustained a moderate soil burn severity, and only 8% burned at high soil burn severity.
Trinity County
Six Rivers Lightning Complex (2022): Combined basin hazard (likelihood + volume) per USGS assessment mostly low to moderate with one larger area of high (segment probability pdf map).
McFarland Fire (2021): Combined basin hazard (likelihood + volume) per USGS assessment is moderate to high (segment probability pdf map).
Monument Fire (2021): Combined basin hazard (likelihood + volume) per USGS assessment is mostly moderate with some areas of high (segment probability pdf map).
River Complex (2021): Combined basin hazard (likelihood + volume) per USGS assessment is moderate to high (segment probability pdf map).
August Complex (2020): Combined basin hazard (likelihood + volume) per USGS assessment is mostly moderate with some areas of high (segment probability pdf map). US Forest Service Burned Area Emergency Response (BAER) assessment for the August Complex-South fire area found approximately 52% of the 521,256 acres analyzed by the BAER team is either unburned/very low (9%) or low (43%) soil burn severity, while 44% sustained a moderate soil burn severity, and only 4% burned at high soil burn severity. For the August Complex-North fire area, approximately 61% of the 551,493 acres analyzed by the BAER team is either unburned/very low (32%) or low (29%) soil burn severity, while 31% sustained a moderate soil burn severity, and only 8% burned at high soil burn severity.
Red Salmon Complex (2020): Combined basin hazard (likelihood + volume) per USGS assessment is mostly moderate with some areas of high (segment probability pdf map).
Tulare County
Coffee Pot Fire (2024): Combined basin hazard (likelihood + volume) per USGS assessment is moderate to high.
KNP Complex (2021): Combined basin hazard (likelihood + volume) per USGS assessment is moderate with a few smaller areas of high (segment probability pdf map).
Windy Fire (2021): Combined basin hazard (likelihood + volume) per USGS assessment is moderate to high (segment probability pdf map).
SQF Complex – Castle Fire (2020): Combined basin hazard (likelihood + volume) per USGS assessment is mostly moderate with some areas of high (segment probability pdf map).
SQF Complex – Rattlesnake Fire (2020): Combined basin hazard (likelihood + volume) per USGS assessment is los to moderate (segment probability pdf map).
Ventura County
Apache Fire (2024): Combined basin hazard (likelihood + volume) per USGS assessment is low to moderate.
Post Fire (2024): Combined basin hazard (likelihood + volume) per USGS assessment is moderate.
Yolo County
LNU Lightning Complex – Hennessey Fire (2020): Combined basin hazard (likelihood + volume) per USGS assessment is mostly low to moderate with a larger area of high south of Lake Berryessa (segment probability pdf map). Cal OES and the California Department of Conservation have released a Watershed Emergency Response Team Evaluation for the Hennessey Fire.