EUGENE, Ore. -- Residents already devastated by the Holiday Farm Fire are now facing another hazard. Recent, wet weather brings the potential for landslides.
Josh Roering, a professor at the University of Oregon and expert in landslides and erosion, said when fire tears through a forest, it not only burns vegetation but incinerates organic material, leaving a Teflon-like coating on the ground giving the perfect runway for water.
“That means that the water starts running across the surface rather than going in the ground and then it starts to pick up all that debris that's accumulated,” Roering said.
The rapid flow of water and sediment becomes a debris flow, reaching speeds up to 20 mph.
Roering said debris flows caused the death of nearly two dozen people in California in 2017 after a wildfire in Montecito.
While there have not been any documented landslides within the Holiday Farm Fire yet, Roering said the roots of dead trees will break down in the coming years, and the danger will increase.
“In the several years after fire, the hillslopes tend to be much more prone to this landsliding process. So that's something we're going to be watching for. Not right now, necessarily, but in the years ahead,” Roering said.
The Oregon Department of Transportation said they have heavy machinery ready to clear the roads if a landslide happens. ODOT spokesman Peter Murphy said the state monitors weather reports closely to know if a change in conditions is expected.
“There could be isolated places where there’s incidents of mud across the road, rocks across the road or rockfalls or anything like that, but by and large that has not happened,” Murphy said.
Murphy said road graders, tractors and other heavy equipment are staged and ready to go to clean up if necessary.
Joe Moll, Executive Director of the McKenzie River Trust, said residents in the fire’s perimeter are already anxious, and the potential for landslides that could cut them off from the rest of the state is only adding fuel to the fire.
“Anytime the prospect of another big disaster -- whether it’s a landslide or winter flood, on top of what people are experiencing already -- that’s a concern,” Moll said.
Moll said he has heard of recovery centers in Vida, Blue River and McKenzie Bridge preparing supplies of food and water in case a landslide or other event were to cut off access to those communities.
Roering said there is some reason to be optimistic. In the last decade, scientists have learned more about stormy weather and how to predict how much rain will fall.
“We are gaining a much more nuanced understanding of the storms we get here in the Pacific Northwest, and what kinds of rainfall amounts they can deliver,” Roering said.