The view

For survivors of California wildfires, next danger could come from water, UB expert says

A devastated neighborhood in the Montecito area of California, downstream from the Thomas Fire that burned in nearby hills.

A devastated neighborhood in the Montecito area of California, downstream from the Thomas Fire that burned in nearby hills. Photo: Chris Renschler

By CHARLOTTE HSU

Published November 15, 2018

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headshot of Chris Renschler.
“One of the biggest problems now is that these fires are happening with a frequency and a scale that we haven’t seen before,” he says. “The sheer size of these burned areas changes the conditions of the landscape in terms of its land cover and rainfall-runoff behavior. ”
Chris Renschler, associate professor
Department of Geography

As deadly wildfires rage in California, the next big risk to areas that have been burned could come from water, says Chris Renschler, a UB expert in integrated watershed management and disaster response.

“Trees and other vegetation have burned away, and where the fire was intense, soils can become hydrophobic. This means the soil absorbs much less water than before, if any, and it can lead to increased surface runoff, creating a higher risk of flash floods and landslides that can endanger both people and property,” says Renschler, associate professor of geography and director of the Landscape-based Environmental System Analysis and Modeling (LESAM) lab at UB.

“It’s something that residents and downstream neighbors of burned areas need to be aware of because even after the fire is extinguished, you can face problems with increased runoff during rain storms.

“One of the biggest problems now is that these fires are happening with a frequency and a scale that we haven’t seen before,” he says. “The sheer size of these burned areas changes the conditions of the landscape in terms of its land cover and rainfall-runoff behavior.”

Flooding, soil erosion and integrated watershed management are important areas of focus for Renschler’s research team that led to the development of watershed modeling techniques that have been used in Burned Area Emergency Response for emergency risk management assessment in post-wildfire situations over the past 15 years.

Chris Renschler, UB associate professor of geography, in the Montecito area of California. He traveled there this summer with a fire captain from the region to view communities devastated by debris flows following wildfires. This photograph shows a tree with bark stripped off many feet off the ground, likely by the Montecito debris flow.

Chris Renschler, UB associate professor of geography, in the Montecito area of California. He traveled there this summer with a fire captain from the region to view communities devastated by debris flows following wildfires. This photograph shows a tree with bark stripped off many feet off the ground, likely by the Montecito debris flow. Photo: Chris Renschler

Renschler notes that in early 2018, mud flows in Southern California took many lives and injured numerous people downstream from areas devastated by wildfires. This summer, he traveled to one of the hardest hit communities — the Montecito area — to gain an understanding of the scope of the destruction by viewing debris flows with a local fire captain who was involved in disaster response.

And landslides are only one of the likely problems that storms can create for communities working to recover from wildfires, Renschler says.

“Think of all the stuff that people have in their homes and garages that burned up and that’s just lying around now,” he says. “Even with less extreme runoff after a storm, ash with all kinds of contaminants — all these toxins — are being rushed down into streams and rivers. From an ecological perspective, streams will be impacted.”