Communities in burn areas at a 'high risk' for slides, flooding with recent rainfall

The relief many have felt from seeing snow and rain is short-lived for those living in the shadow of the steep slopes and mountainsides burned by the late-season fires.

Communities in those areas now face concerns over landslides and flash flooding. 

The Department of Natural Resources (DNR) and residents are keeping a close eye on the situation. The DNR says some of the most vulnerable spots include land that sits in a high drainage area called an Alluvial Fan, which includes the unincorporated area of Grotto in King County. 

"I knew that there was going to be trees falling," said Betsy Wright, of Grotto.   

She said she's already heard the trees crashing onto US 2 in an area scarred by fire. One recently fell just under a mile from her home with a thunderous boom.  

"I heard it, and it’s scary," said Wright. 

The DNR has specifically warned Grotto to be alert for landslides and debris flows. 

"The community of Grotto is on an Alluvial Fan and the basin above them is modeled as high risk," said Kate Mickelson, Landslide Hazards Program Manager with the DNR. "What we like to tell people is they need to watch for impending storms."

Mickelson says the concern also extends beyond this first rainfall of the season.  

"What a wildfire does is it can change the soil to be more erodible and cause excess runoff.  They could see excess runoff this winter and as tree roots decay over the coming years, we could see larger events," said Mickelson. 

Wright's neighborhood was also one of the first to evacuate from the Bolt Creek Fire. She says the fire stopped around 300 feet away from her house and shared some pictures of an area that had burned near her property.

"When we got kicked out of here on Saturday the 10th we thought we were losing everything," said Wright. 

She's also aware of the latest concern: flash flooding. Not far from her home a sign on the highway reads, "Flash Flood Danger" from her community through Skykomish

Grotto sits in an area already prone to flooding. 

"Our street becomes a river when it rains," said Wright. "I have a weather machine on my roof, so it records how much rain we get and it is not uncommon to get five inches of rain in an hour. It happens. Ten inches in a day."

Wright says her husband has told her to flee to higher ground in the event of a slide or debris flow. She says he's identified one possible route so far. 

"I don’t know how you escape a mud flow, I have no idea," said Wright. "I always keep an eye on the ditches, I keep an eye on our rainfall. I guess that’s about what you can do." 

The DNR says you should also be on the lookout for flash flood warnings from the National Weather Service. You can find more information on what to do in a mudslide here. 

Mickelson says the DNR is in the early stages of gathering data on slides and the impacts of wildfire in Western Washington. She says it's estimated that the largest debris flows could happen up to five years or longer after the fire.  

She says the DNR will be installing weather gauges in the coming weeks to better study the impacts of the Bolt Creek Fire on slides.