Geologists warn of potentially ‘destructive landslides’ across Oregon Cascades this weekend

PORTLAND, Ore. ( KOIN ) — With the National Weather Service’s Portland office issuing a Flash Flood Watch weather alert as severe weather potentially looms for the region on Saturday, geological experts are warning landslides may happen this weekend for portions of the Oregon Cascades.

A Flash Flood Watch is in effect from Saturday afternoon through late Sunday night and includes the Cascades of Lane County, Cascades of Marion and Linn Counties and the North Oregon Cascades, according to the NWS.

Not only is heavy rainfall expected in the region, but it could result in landslides and debris flows in steep terrain areas as well as recently burned wildfire areas, according to the Oregon Department of Geology and Mineral Industries (DOGAMI).

“Debris flows are rapidly moving, extremely destructive landslides. They can contain boulders and logs transported in a fast-moving soil and water slurry down steep hillsides and through narrow canyons. They can easily travel a mile or more,” officials at DOGAMI said in a release. “A debris flow moves faster than a person can run. People, structures, and roads located below steep slopes in canyons and near the mouths of canyons may be at serious risk.”

People who live, work or travel in the affected areas are advised to do the following:

• Stay alert. Track the flood watch by radio, TV, weather radio or online. If told to evacuate, do so immediately.
• Listen. Unusual sounds might indicate moving debris, such as trees cracking or boulders knocking together. A trickle of falling mud or debris may precede larger landslides. If you think there is danger of a landslide, leave immediately.
• Watch the water. If water in a stream or creek suddenly turns muddy or the amount of water flowing suddenly decreases or increases, this is a warning that the flow has been affected upstream. You should immediately leave the area because a debris flow may soon be coming downstream.
• Travel with extreme caution. Assume roads are not safe. Be alert when driving, especially at night. Embankments along roadsides may fail, sending rock and debris onto the road.

More information about landslides and debris flows can be found on the State of Oregon’s website .

For the latest news, weather, sports, and streaming video, head to KOIN.com.