Postfire Landslide Monitoring Station: “Las Lomas” (2016 Fish Fire) near Duarte, California Active
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.
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.