Study finds that wildfires will trigger more landslides in California

The American Geophysical Union (AGU) reported that Southern California is likely to begin experiencing an increase in post-wildfire landslides, according to a new study.

The study reports that Californians will face the risk of wildfire and landslide risks rising as a result of shifting climate change in both wet and dry seasons. 

“This is our attempt to get people thinking about where these hazards are going to be before there’s even a fire,” Jason Kean, a hydrologist at the U.S. Geological Survey in Denver and lead author of the new study in Earth’s Future, AGU’s journal, said. “By proactively thinking about hazards, you can start to develop more detailed response plans for their inevitability.”

The connection between wildfires and landslides is due to the fact that water will liquefy unstable soil and vegetation which has been burnt. Unfortunately, there is rarely sufficient time between fire and heavy rains to put into practice a solid emergency response plan. 

The study conducted by AGU found that small landslides are now to be expected nearly every year in southern California and that major landslides which can damage more than 40 structures will occur every 10-13 years, which is about as common as 6.7-magnitude earthquakes. More heavy rainfall is also likely to occur in the coming years, which will lead to a higher frequency of landslides. 

Shortening seasons in the state also indicates that California will be dealing with more wildfire and post-wildfire landslides, which will result in more danger for individuals who live in the state.

“We’re going to have a longer season to burn and then when it does rain, it’s going to come down harder. And that’s a bad recipe for these post-fire debris flows,” Kean said. “The reason you can expect one just about every year is because it doesn’t take very much rain to cause one. The rainstorms that can trigger debris flows – they’re kind of garden-variety storms.”