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Crews watching for debris flows as rain helps fight Nakia Creek Fire

PORTLAND, Ore. (KOIN) — While the rain is helping fight the Nakia Creek Fire in Clark County, it’s also creating the potential for another hazard — mudslides.

After days of crews’ continuous efforts, fire officials told KOIN 6 News on Friday that the containment lines are now fully established around the roughly 1,918-acre blaze. They are currently focused on the mop-up stage, which is the labor-intensive process of extinguishing or removing material that’s burning within the soil.

Not only are firefighters working in the rain and colder temperatures, but they also now have to be on alert for debris flow, according to Portland State University geology professor Scott Burns.

“If they’re working on the upland surfaces, it’s a sticky muddy type of situation. But if they are down in the valleys, they could just all of a sudden be overwhelmed with a whole bunch of water that is coming down and this slurry that is coming down [which] we call a debris flow,” Burns explained.

The Oregon Department of Forestry has said they’ve been looking ahead and planning for the rain for several days.

In terms of crew safety, ODF says a lot of it comes down to firefighters being aware of their surroundings. However, there is work is being done to mitigate potential hazards — including creating “water bars” across roads, giving the water a way to funnel off the road.

“It really just looks like a kind of a diagonal speed bump across the road, usually of gravel or dirt and it just helps keep the integrity of the road so that it’s not sliding off the hill as well,” ODF’s Natalie Weber said.

Furthermore, Weber says firefighters are having to be aware of trees and large branches falling due to added water weight.

For people living in the area, Burns extended a word of caution — especially those who live downstream.

“You will have a lot of erosion, lot of sediment and/or organic debris [that] will get into the streams and make its way downstream,” he explained. “You can be many miles away and affected by material coming out of a burned area.”

ODF says they will soon be handing control back over to the Washington State Department of Natural Resources.