The answers to when and where the next debris flow might occur could be just below the surface of our soil.
After a fire, vegetation is damaged, causing soil to become unstable. Add some heavy rain and BAER Program Coordinator Yonni Schwartz says, "You have all that soil erosion, fine sediments flowing into the drainage, then starting to mobilize as mud and a lot of water. The conditions here are ideal for postfire landslides and debris flows."
USGS Research Hydrologist, Matthew Thomas explains that after the deadly 2018 debris flow in Montecito USGS, the California Geological Survey, and the forest service created a landslide monitoring program collecting data on how vegetation affects soil stability after a fire.
"As these burn areas recover, the landslides may be strongly tied to how that vegetation recovers in that burned area over time," said Thomas
After heavy rain in January 2023, the monitors recorded 1,200 landslides above Montecito and 10,000 above Santa Barbara - these landslides were much smaller and less impactful on communities than in 2018. Don Lindsay with California Geological Survey says monitoring slopes gives valuable insight into how our mountains will act in the future.
"These slope monitoring stations provide a unique look at the control vegetation has on runoff and with it, it should provide an increased ability to predict runoff hazards like flooding to debris flow hazards," said Lindsay.
The data collected will hopefully expand understanding of where, how, and when soil failure can happen and better emergency planning and responses for high-risk areas.
"Our goal would be to develop the knowledge we need to have conversations with the weather service before large rainstorms, to provide input on the likelihood of landslides developing in response to a storm," said Thomas
To view hourly data from the program visit - USGS.gov
