Debris flow and recent burn areas

Infographic: Debris flow and recent burn areas

Dec. 23, 2015 8:48 AM PT

The U.S. Geological Survey has studied select fire burn areas to determine their vulnerability to flash floods and debris flows. Using burn severity, soil properties, rainfall data based on a 25-year storm and a number of other factors, scientists have estimated the likelihood of a debris flow during weather similar to what could occur in a strong El Niño season.

Key (click and zoom in to maps for details)

Fire perimeters

High chance of debris flow

Moderate chance of debris flow

Low chance of debris flow

Colby fire

Jan. 16, 2014 The Colby fire burned 1,952 acres and destroyed 10 buildings, including 5 residences. The same area also burned in 1968, and a powerful storm in 1969 produced a debris flow that damaged a large number of homes.

Silverado fire

Sept. 12, 2014 The Silverado fire burned 968 acres in an area with steep terrain, chaparral and brush. The area has had a history of debris flows. In February, 1969, mud and debris swept into a fire station in Silverado Canyon, and flood refugees who had sought shelter there were carried out through the doors into the road in front of the station — five were killed and about 20 others were injured.

Lake fire

June 17, 2015 The Lake fire burned 31,359 acres and destroyed one residence and three outbuildings.

Rough fire

July 31, 2015 The Rough fire burned 151,623 acres and destroyed four structures.

Butte fire

Sept. 9, 2015 The Butte fire burned 70,868 acres, destroying 475 residences and 343 outbuildings.

Valley fire

Sept. 12, 2015 The Valley fire burned 76,067 acres and destroyed 1,955 structures, including 1,281 homes.

Sources: Jason Kean, U.S. Geological Survey; Inciweb, CalFire

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Raoul Rañoa

Raoul Rañoa is a former senior graphics and data journalist at the Los Angeles Times.

Rosanna Xia

Rosanna Xia is an environment reporter for the Los Angeles Times, where she specializes in stories about the coast and ocean. She was a Pulitzer Prize finalist in 2020 for explanatory reporting, and her award-winning book, “California Against the Sea,” has been praised as a poetic and mind-expanding exploration of what we stand to lose in the face of rising water.