As the rainy season begins in California, so too does the potential for dangerous flash flooding. That’s especially true for areas burned by wildfires. Some wildfires that occurred just last year in Lake County and the coastal ranges of California need as little as a half inch of rain in an hour to cause erosion and debris flows.
“Just because you aren’t in the burn scar doesn’t mean that you’re not at risk," says Michelle Mead with the National Weather Service. "If you’re downstream of that burn scar, if we do get a flash flooding event, that could actually impact you with just the water runoff and/or debris flow.”
Severely burned soil can also increase the rate and frequency of water runoff, says Drew Coe, a hydrologist with Cal Fire.
"We have research going on in the Valley Fire, which burned in 2015, that indicates severely burned areas are producing up to 15 times higher rates of runoff than areas with lower soil burn severity,"says Coe.
A list of recommended preparation steps and resources can be found at FloodPrepareCA.com.
An online educational video shows recent catastrophic flooding after fire events across California.