Wildfire can increase landslide susceptibility in mountainous terrain. The USGS maintains postfire landslide monitoring stations to track hillslope hydrologic conditions in the years following fire.
Recent Conditions
Instrumentation was installed within the footprint of the 2016 Fish Fire in the San Gabriel Mountains of southern California. The surface and subsurface data are used to monitor and detect changes in local hillslope hydrologic conditions. Soil-water content, soil suction, soil temperature, and groundwater pressure are measured in a single nest on the same hillslope. Telemetered data for the site include:
- Rainfall
- Air temperature and relative humidity
- Soil-water content, soil suction, soil temperature, and groundwater pressure head
- Battery voltage
Data are recorded every minute and updated on the graphs every 60 minutes.
Project Background
Soon after the 2016 Fish Fire, the U.S. Geological Survey observed runoff-generated debris flows in the “Las Lomas” catchment. Three years after the fire, the same area experienced shallow landslides, which mobilized into debris flows. The apparent shift in the debris-flow generation mechanism (i.e., surface-water runoff versus subsurface pore-water pressure) was attributed to postfire soil-hydraulic recovery and vegetation regrowth. To resolve process-based controls on postfire landsliding and to contribute to the development of antecedent soil moisture and rainfall thresholds for the region, a monitoring station was installed in the Las Lomas drainage area within the Angeles National Forest. The surface and near-surface hydrologic monitoring will provide valuable constraints on the conditions leading up to, and during, rainstorms that produce landslides.
Post-wildfire debris-flow monitoring data, Las Lomas, 2016 Fish Fire, Los Angeles County, California, November 2016 to February 2017
Postwildfire soil‐hydraulic recovery and the persistence of debris flow hazards
Landslides after wildfire: Initiation, magnitude, and mobility
- Overview
Wildfire can increase landslide susceptibility in mountainous terrain. The USGS maintains postfire landslide monitoring stations to track hillslope hydrologic conditions in the years following fire.
Recent Conditions
Instrumentation was installed within the footprint of the 2016 Fish Fire in the San Gabriel Mountains of southern California. The surface and subsurface data are used to monitor and detect changes in local hillslope hydrologic conditions. Soil-water content, soil suction, soil temperature, and groundwater pressure are measured in a single nest on the same hillslope. Telemetered data for the site include:
- Rainfall
- Air temperature and relative humidity
- Soil-water content, soil suction, soil temperature, and groundwater pressure head
- Battery voltage
Data are recorded every minute and updated on the graphs every 60 minutes.
A landslide monitoring station within the footprint of the 2016 Fish Fire in the San Gabriel Mountains of southern California. The station collects surface and subsurface data to monitor and detect changes in local hillslope hydrologic conditions. Project Background
Soon after the 2016 Fish Fire, the U.S. Geological Survey observed runoff-generated debris flows in the “Las Lomas” catchment. Three years after the fire, the same area experienced shallow landslides, which mobilized into debris flows. The apparent shift in the debris-flow generation mechanism (i.e., surface-water runoff versus subsurface pore-water pressure) was attributed to postfire soil-hydraulic recovery and vegetation regrowth. To resolve process-based controls on postfire landsliding and to contribute to the development of antecedent soil moisture and rainfall thresholds for the region, a monitoring station was installed in the Las Lomas drainage area within the Angeles National Forest. The surface and near-surface hydrologic monitoring will provide valuable constraints on the conditions leading up to, and during, rainstorms that produce landslides.
- Data
Post-wildfire debris-flow monitoring data, Las Lomas, 2016 Fish Fire, Los Angeles County, California, November 2016 to February 2017
This data release includes time-series data from a monitoring site located in a small (0.12 km2) drainage basin in the Las Lomas watershed in Los Angeles County, CA, USA. The site was established after the 2016 Fish Fire and recorded a series debris flows in the first winter after the fire. The station is located along the channel at the outlet of the study area (34 9'18.50"N, 117 56'41.33"W, WGS8 - Publications
Postwildfire soil‐hydraulic recovery and the persistence of debris flow hazards
Deadly and destructive debris flows often follow wildfire, but understanding of changes in the hazard potential with time since fire is poor. We develop a simulation‐based framework to quantify changes in the hydrologic triggering conditions for debris flows as postwildfire infiltration properties evolve through time. Our approach produces time‐varying rainfall intensity‐duration thresholds for ruAuthorsMatthew A. Thomas, Francis K. Rengers, Jason W. Kean, Luke A. McGuire, Dennis M. Staley, Katherine R. Barnhart, Brian A. EbelLandslides after wildfire: Initiation, magnitude, and mobility
In the semiarid Southwestern USA, wildfires are commonly followed by runoff-generated debris flows because wildfires remove vegetation and ground cover, which reduces soil infiltration capacity and increases soil erodibility. At a study site in Southern California, we initially observed runoff-generated debris flows in the first year following fire. However, at the same site three years after theAuthorsFrancis K. Rengers, Luke McGuire, Nina S. Oakley, Jason W. Kean, Dennis M. Staley, Hui Tang