Recent Landslide Hazard Assessments

WARNING! Everyone within and downstream of burned areas should remain alert and stay updated on weather conditions that may result in heavy rains over the burn scars. Flash flooding and debris flows may occur quickly during heavy rain events—be ready to evacuate on short notice. Learn how to prepare at our web page "Post-Wildfire Debris Flows."

2021 Post-Wildfire Watershed Emergency Response

Updated October 25, 2021

CAL FIRE and the California Geological Survey deployed Watershed Emergency Response Teams (WERTs) to this year's major burns located in state responsibility areas (Caldor fire, Dixie fire, French fire, and Alisal fire).

To learn how the CGS works with CAL FIRE and others to analyze landslide potential on newly burned landscapes, visit the CalConservation blog: Notes from the Field.

Requests for WERT report information should be directed to CAL FIRE. (CAL FIRE by default provides WERT hazards evaluation reports and maps to affected communities, flood control managers, and emergency managers.)

Landslide Watch

California Landslide Watch - Curated tweets

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2020 Post-Wildfire Watershed Emergency Response

Updated October 25, 2021

Enhanced landslide hazards continue to exist in the 2020 wildfire areas. A typical watershed recovery period after fire is two to five years; but in some areas it can take up to ten years as trees die and roots decay. Please keep this in mind and plan accordingly.

Apple and El Dorado Fires

Counties Affected: Riverside and San Bernardino.
Burn Area Map: N.W.C.G. Apple and El Dorado Fires web map.
Assessment of Post-Fire Debris Flow Hazards:

Additional Information:

Blue Ridge Fire

Counties Affected: Orange and Riverside.
Burn Area Map: N.W.C.G. Blue Ridge Fire web map.
Assessment of Post-Fire Debris Flow Hazards:

U.S.G.S. Blue Ridge Fire Post-Fire Debris Flow Hazards web page.
U.S.F.S. Post-Fire B.A.E.R.: Not available (not U.S.F.S. jurisdiction).

Additional Information:

CAL FIRE Blue Ridge Fire Incident Archive.
InciWeb Blue Ridge Fire information: Not available.

Bond and Silverado Fires

Counties Affected: Orange.
Burn Area Map: N.W.C.G. Bond and Silverado Fires web map.
Assessment of Post-Fire Debris Flow Hazards:

U.S.G.S. Bond Fire Post-Fire Debris Flow Hazards web page.
U.S.G.S. Silverado Fire Post-Fire Debris Flow Hazards web page.
U.S.F.S. Post-Fire B.A.E.R.: Not available (not U.S.F.S. jurisdiction).

Additional Information:

CAL FIRE Bond Fire Incident Archive.
CAL FIRE Silverado Fire Incident Archive.
InciWeb Bond and Silverado Fires information: Not available.

Carmel Fire

Counties Affected: Monterey.
Burn Area Map: N.W.C.G. Carmel Fire web map.
Assessment of Post-Fire Debris Flow Hazards:

U.S.G.S. Carmel Fire Post-Fire Debris Flow Hazards web page.
U.S.F.S. Post-Fire B.A.E.R.: Not available (not U.S.F.S. jurisdiction).

Additional Information:

CAL FIRE Carmel Fire Incident Archive.
InciWeb Carmel Fire information: Not available.

Creek Fire

Counties Affected: Fresno and Madera.
Burn Area Map: N.W.C.G. Creek Fire web map.
Assessment of Post-Fire Debris Flow Hazards:

Additional Information:

CZU Lightning Complex

Counties Affected: Santa Cruz and San Mateo.
Burn Area Map: N.W.C.G. CZU Lightning Complex web map.
Assessment of Post-Fire Debris Flow Hazards:

U.S.G.S. CZU Lightning Complex Post-Fire Debris Flow Hazards web page.
U.S.F.S. Post-Fire B.A.E.R.: Not available (not U.S.F.S. jurisdiction).

Additional Information:

CAL FIRE CZU Lightning Complex Incident Archive.
InciWeb CZU Lightning Complex information: Not available.

Glass Fire

Counties Affected: Sonoma and Napa.
Burn Area Map: N.W.C.G. Glass Fire web map.
Assessment of Post-Fire Debris Flow Hazards:

U.S.G.S. Glass Fire Post-Fire Debris Flow Hazards web page.
U.S.F.S. Post-Fire B.A.E.R.: Not available (not U.S.F.S. jurisdiction).

Additional Information:

CAL FIRE Glass Fire Incident Archive.
InciWeb Glass Fire information: Not available.

LNU Lightning Complex - Hennessy Fire

Counties Affected: Napa, Solano, Yolo, Lake, and Colusa.
Burn Area Map: N.W.C.G. Hennessey Fire web map.
Assessment of Post-Fire Debris Flow Hazards:

U.S.G.S. Hennessey Fire Post-Fire Debris Flow Hazards web page.
U.S.F.S. Post-Fire B.A.E.R.: Not available (not U.S.F.S. jurisdiction).

Additional Information:

CAL FIRE LNU Lightning Complex Incident Archive.
InciWeb LNU Lightning Complex information: Not available.

LNU Lightning Complex - Walbridge and Meyers Fires

Counties Affected: Sonoma.
Burn Area Map: N.W.C.G. Walbridge and Meyers Fires web map.
Assessment of Post-Fire Debris Flow Hazards:

U.S.G.S. Walbridge Fire Post-Fire Debris Flow Hazards web page.
U.S.G.S. Meyers Fire Post-Fire Debris Flow Hazards web page.
U.S.F.S. Post-Fire B.A.E.R.: Not available (not U.S.F.S. jurisdiction).

Additional Information:

CAL FIRE LNU Lightning Complex Incident Archive.
InciWeb LNU Lightning Complex information: Not available.

North Complex

Counties Affected: Plumas and Butte.
Burn Area Map: N.W.C.G. North Complex web map.
Assessment of Post-Fire Debris Flow Hazards:

U.S.G.S. North Complex Post-Fire Debris Flow Hazards web page.
U.S.G.S. North Complex - Claremont Post-Fire Debris Flow Hazards web page.
U.S.F.S. North Complex Post-Fire B.A.E.R.: Not available.

Additional Information:

River Fire

Counties Affected: Monterey.
Burn Area Map: N.W.C.G. River Fire web map.
Assessment of Post-Fire Debris Flow Hazards:

U.S.G.S. River Fire Post-Fire Debris Flow Hazards web page.
U.S.F.S. Post-Fire B.A.E.R.: Not available (not U.S.F.S. jurisdiction).

Additional Information:

CAL FIRE River Fire Incident Archive.
InciWeb River Fire information: Not available.

SCU Lightning Complex

Counties Affected: Santa Clara, Alameda, San Joaquin, Stanislaus, and Merced.
Burn Area Map: N.W.C.G. SCU Lightning Complex web map.
Assessment of Post-Fire Debris Flow Hazards:

U.S.G.S. SCU Lightning Complex Post-Fire Debris Flow Hazards web page.
U.S.F.S. Post-Fire B.A.E.R.: Not available (not U.S.F.S. jurisdiction).

Additional Information:

CAL FIRE SCU Lightning Complex Incident Archive.
InciWeb SCU Lightning Complex information: Not available.

Snow Fire

Counties Affected: Riverside.
Burn Area Map: Not available.
Assessment of Post-Fire Debris Flow Hazards:

Additional Information:

Images from the Field

Select any photo to open it full size in a new window.

Two individuals posing near a helicopter.

WERT members prepare to perform aerial reconnaisance of post-fire hazards. Photo credit: Ellie Spangler, CGS. August 29, 2020.

Mountains denuded by wildfire loom over homes on flat land below.

RIVER FIRE: Burned mountainous terrain above homes in the Pine Canyon area near Salinas, California (Monterey County). These conditions are a concern because of potential for debris flows. Photo credit: Brian Swanson, CGS. August 31, 2020.

A steep slope of a narrow canyon. A road follows the canyon bottom.

CARMEL FIRE: Burned steep slope above Cachagua Road showing extensive dry ravel and associated rockfall hazard in Monterey County, California. Photo credit: Brian Swanson, CGS. August 31, 2020.

An individual taking notes at the base of a burned slope.

RIVER FIRE: Documenting a potential debris flow hazard above a county road. Monterey County, California. Photo credit: Ellie Spangler, CGS. August 30, 2020.

Blackened skeletons of trees and shrubs stand watch over miles of burned hills.

SCU LIGHTNING COMPLEX: Burned hillslopes above Pulse Canyon near San Antonio Valley. Santa Clara County, California. Photo credit: Ellie Spangler, CGS. September 6, 2020.

Four individuals hiking up a charred hillside.

RIVER FIRE: A CGS and CAL FIRE team performing ground reconnaisance of post-fire hazards. Photo credit: Ellie Spangler, CGS. August 29, 2020.

A steep gully denuded by fire. Bare soil and boulders are all that remain.

SCU LIGHTNING COMPLEX: Potential debris flow hazard on Oak Ridge, near Mount Hamilton. Santa Clara County, California. Photo credit: Ellie Spangler, CGS. September 5, 2020.

Two individuals on a charred hillside. One of the individuals is reaching down to the ground while the other observes.

RIVER FIRE: Don Lindsay (CGS) and Brian Mattos (CAL FIRE) assessing the water repellency of burned soil on a hillside. Monterey County, California. Photo credit: Ellie Spangler, CGS. August 29, 2020.

David Longstreth, senior engineering geologist in California Geological Survey’s (CGS) Forest and Watershed Geology program, is one of many in the field studying burn areas in the Santa Cruz area after the CZU Lightning Complex. He is determining risk communities can expect come rainy season:

Watershed Emergency Response Teams

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. The WERT response is led by the California Department of Forestry and Fire Protection (CAL FIRE) and co-led by the California Geological Survey (Department of Conservation).

The WERT five-step process to risk reduction: 1. Determine soil burn severity. 2. Identify values at risk. 3. Identify, model, and classify hazards. 4. Develop emergency protective measure(s). 5. Communicate findings. WERT objectives are completed in a rapid step-wise manner to achieve the goal of risk reduction. A fundamental step in the WERT process is the identification and characterization of values-at-risk (VARs). VARs are the values or resources at risk of damage or loss by post-wildfire geologic and/or hydrologic hazards. The WERT process utilizes a qualitative approach to evaluate risk to these values, and relies on a combination of modeling and best professional judgment to guide relative risk determination and the development of emergency protection measures. The final step in risk reduction is to communicate the evaluation findings to local jurisdictions responsible for emergency planning and preparedness.

The decision to conduct a WERT response is made by CAL FIRE in coordination with local and federal agencies, and is also based on:

Fire size and intensity, and its location in relation to values-at-risk (VARs).
Proximity of intensely burned areas with steep slopes to housing developments.
Likelihood of debris flows based on topography, geology, climate, etc. impacting VARs.
Proximity of VARs to flood and debris flow prone areas affected by the fire.
Presence of transportation networks, water supply systems, campgrounds, etc. at potentially high risk.
Fire that includes a significant percentage of state responsibility areas.

A large smoke column rises thousands of feet above chaparral-covered mountains. — Smoke column above the Lake Fire (2020). Photo credit: Austin Dave.

Web page by:
California Regional Geologic and Landslide Mapping Program

Recent Landslide Hazard Assessments

2021 Post-Wildfire Watershed Emergency Response

Landslide Watch

2020 Post-Wildfire Watershed Emergency Response

Apple and El Dorado Fires

Blue Ridge Fire

Bond and Silverado Fires

Carmel Fire

Creek Fire

CZU Lightning Complex

Glass Fire

LNU Lightning Complex - Hennessy Fire

LNU Lightning Complex - Walbridge and Meyers Fires

North Complex

River Fire

SCU Lightning Complex

Snow Fire

Images from the Field

Watershed Emergency Response Teams

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2021 Post-Wildfire Watershed Emergency Response

Landslide Watch

2020 Post-Wildfire Watershed Emergency Response

Apple and El Dorado Fires

Blue Ridge Fire

Bond and Silverado Fires

Carmel Fire

Creek Fire

CZU Lightning Complex

Glass Fire

LNU Lightning Complex - Hennessy Fire

LNU Lightning Complex - Walbridge and Meyers Fires

North Complex

River Fire

SCU Lightning Complex

Snow Fire

Images from the Field

Watershed Emergency Response Teams