Images

Rain gauge in Glenwood Canyon, Colorado. After the 2020 Grizzly Creek fire, scientists installed a network of rain gauges and soil moisture sensors throughout the rugged burn area. These instruments provide real-time data on rainfall intensity and duration, which are critical factors in determining the likelihood of a debris flow. 

Three soil moisture sensors shown before their installation in a soil pit. The sensors will form a vertical subsurface array geared to track infiltration behavior. 

This photograph of a small watershed within the 2020 Calwood Fire burn area, Boulder County, Colorado was taken 6 months following the fire.  The removal of vegetation and change in soil properties make steeply burned areas susceptible to postfire debris flows.  

Soil pit shown with three soil moisture sensors installed in a subsurface vertical array. The wetting and drying of the soil will be tracked over multi-annual timescales. 

Scientists installed a hillslope monitoring station following the 2020 Calwood Fire, Boulder County, Colorado.  These monitoring stations help to collect data, such rainfall and soil moisture, that is used to better understand postfire debris-flow processes.

A soil moisture sensor shown prior to installation in a soil pit. This kind of sensor measures the dielectric constant of the soil using capacitance and frequency domain technology.

Hillslopes in the 2020 Calwood Fire burn area covered by burned and partially burned trees. This photo was taken approximately 6 months after the fire.  

Scientists install the 'Heil Ranch' monitoring station on a steeply burned hillslope within the 2020 Calwood Fire burn area, Boulder County, Colorado.  The monitoring station collects data following wildfire to support research on postfire debris-flow processes.

Postfire monitoring station within the 2020 CZU Lightning Complex burn area.  This photograph was taken in February 2021 approximately 4.5 months after the fire was contained.  

Postfire monitoring station within the 2020 CZU Lightning Complex burn area.  This photograph was taken in February 2021 approximately 4.5 months after the fire was contained.  

Rilling and a shallow landslide in CZU Fire near Eagle Rock, California. Soil ~3 cm below surface was almost completely dry after the rain storm, highlighting soil water repellancy.  

The effects of debris floods following the 2020 River Fire in Monterey County, California. 

Photo credit: Matthew A. Thomas, U.S. Geological Survey

The storm that hit California’s coast between Jan. 26 and 28, 2021, blew out a portion of Hwy 1 near Big Sur. On Saturday, a USGS reconnaissance flight snapped this dramatic photo above the Rat Creek drainage showing the debris flow.

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.

 Debris flow deposit at the outlet of the Tumalt Creek drainage basin, Columbia River Gorge, Oregon,  following storms in January 2021.

USGS scientist monitors the burn area following the Grizzly Creek fire of 2020 in Glenwood Canyon, Colorado. 

Burned trees following the 2020 Grizzly Creek fire in Glenwood Canyon, Colorado. 

An image of 24 June 2020 (B4) and prehistoric (P2) outlier rockfall boulders within the Mount Whitney Trailhead Campground. Boulder P2 is approximately 3 m tall. The blue dashed line indicates one of several tent sites affected by the 2020 rockfalls.

Images showing the flyrock trajectory from the 24 June 2020 rockfall (see previous figure). Rock impacts at the base of the talus slope split and moved boulders, launching a 0.5 cubic meter boulder 92 m into the lower parking lot at Whitney Portal.

Barry Arm of Harriman Fjord, Prince William Sound, Alaska. Included is Barry Glacier and Cascade Glacier.

Debris flow deposits caused by intense rainfall in April 2020 block a highway in Macon County, NC.