Landslides a concern following summer fires and fall rain

Officials say the landslide on Mercer Lake Road took out trees and power lines. There's no estimate on when the road will re-open. Photo courtesy Lane County Public Information

Beyond slick roads, a heavy downfall can cause several problems following the active wildfire season we've seen in Oregon this summer.

Burnt land is more susceptible to landslides and erosion.

Experts say it's probably not time to worry just yet, but if certain factors align, we could start seeing some trouble.

One of the biggest issues following a fire is figuring out where the water will go, and Oregon will get the first taste of that next week.

"Fire comes, storms come, slope instability happens. Debris flows can occur and material can move," said Gordon Grant, a Research Hydrologist for the U.S. Forest Service.

Fire tends to make landslides more likely for several reasons, one of which is that it kills trees that typically hold the soil together.

Oregon already has steep terrain that's prone to slide.

"You lose the trees, you lose the roots, you lose the cohesion," said Grant. "Then you bring a storm in, you generate the pressures, you create landslides, you create debris flows and then they run off and cause all kinds of mischief."

Grant says it's not an urgent concern, but it could happen given all of the fires we've seen.

One of the major concerns is the Columbia River Gorge due to the steep terrain there. There is also potential for debris to get into the McKenzie River from the hillsides east of Eugene.

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