Rising Debris Flow Risks Dangerous Link Between Wildfires, Rainfall, and Climate Change
Debris flows, fast-moving masses of mud, rocks, and water, are becoming a growing concern in the United States, particularly in areas recently affected by wildfires. A map produced by the U.S. Geological Survey (USGS) highlights high-risk zones near Los Angeles after the Palisades Fire. The model simulates a scenario where 15 minutes of rainfall, at just under 1 inch (24 mm) per hour, could trigger debris flows in vulnerable regions.
The landscape itself can create ideal conditions for debris flows. Steep slopes, the presence of clay-rich soil, and silt-sized particles in watersheds are key contributors. Generally, slopes gentler than 23 degrees and lacking fine-grain materials are less likely to experience debris flows.
Post-wildfire conditions worsen the risk. Severely burned areas...
