Debris flow
Aftermath of a debris flow near a home in Montecito, California, following the January 2018 Thomas Fire. (Photo: Courtesy of Jason Kean)

The Thomas Fire raged through Montecito, California in 2017, destroying homes and forests. But even after the fire was contained, more tragedy followed. When heavy rain hit the scorched earth, it caused deadly flooding and mud flows.

Jason Kean of the U.S. Geological Survey says that a barren, charred landscape cannot absorb much water.

Kean: “It behaves more like a parking lot than a natural ground surface. Water runs off very fast. And in steep areas it can turn into something we call a debris flow, which is roughly half water, half sediment, and can have boulders, trees and logs, and is even more dangerous than a flood.”

As global warming contributes to larger and more severe wildfires, the risk of dangerous, even deadly debris flows is likely to grow.

So Kean says it’s important for residents in areas that have experienced wildfires to stay tuned to alerts and evacuate when told to do so.

Kean: “It’s very tough. Often these people had to just evacuate from the wildfire, and now they have to evacuate again for the rainfalls. But as we’ve seen just last year, these things can be fatal, so they have to take them seriously.”

Reporting credit: Daisy Simmons/ChavoBart Digital Media.

Filed under: