After a wildfire, how intense does rainfall need to be to cause a debris flow?
A research team from the University of Arizona Geosciences, AZGS, and the US Geological Survey are deploying monitoring devices in burned areas in the Southwestern U.S. to address that question.
Debris flows are mixtures of water, soil, and rock (think flowing concrete) that behave different from floods. Because debris flows are a thick slurry and can carry large boulders and trees, they can generate high impact forces which may damage buildings and infrastructure and, more importantly, pose significant threat to human life and safety. In recently burned landscapes, there is frequently a rapid switch from floods to debris flows once a critical rainfall intensity is exceeded.