Heavy Weekend Rains Bring Possibility of Landslides

Heavy rains are predicted around the state this weekend. Our news partner, The Seattle Times, reports that from Saturday evening to late Monday, the Olympic range could get as many as eight inches of rain and that parts of the Cascades could get as many as five inches.

While the break in the dry weather may be good news for putting an end to more than a month of wildfires around the state, National Forest officials say the rainstorms could also set the stage for landslides.

Danger around drainages

Hikers should be very cautious around any steep drainages, along hillsides, some shorelines and on snowfields.

Drainages around Mount Adams, Gifford Pinchot National Forest officials say, will be especially vulnerable due to recent fire activity.

Tom DeRoo, a hydrologist working on rehabilitating the fire area on Mount Adams, says the predicted rains may be enough in a short enough time to create landslides.

“This is the kind of storm that can trigger debris flows down channels anywhere around the mountain depending on where the rain goes.” DeRoo says. “This can happen whenever it rains like this, unrelated to the fire.”

He predicts that  most affected drainages will be Cascade, Morrison, Salt and Crofton creeks, along with any of the major drainages around the forest.

“Downstream, there is the possibility of a muddy flood in the White Salmon and other rivers,” DeRoo says.

Past impacts of landslides, mudslides, flooding

Landslides resulting from floods in 2003 and 2006 have kept the Suiattle River Road closed past milepost 12, locking out hikers from some of the best trails in the North Cascades. (WTA and hikers have long been advocating for the road's repair.)

Flooding can also erode and damage trails. Washington Trails Association volunteer crews often help repair or work to protect trails from flooding.

If you see a landslide, report it to the Department of Natural Resources.