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)
High chance of debris flow
Moderate chance of debris flow
Low chance of debris flow
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.
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.
June 17, 2015 The Lake fire burned 31,359 acres and destroyed one residence and three outbuildings.
July 31, 2015 The Rough fire burned 151,623 acres and destroyed four structures.
Sept. 9, 2015 The Butte fire burned 70,868 acres, destroying 475 residences and 343 outbuildings.
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