Landslide warnings issued just as two slides hit Oregon Coast

Landslide warnings issued just as two slides hit Oregon Coast

PORTLAND, Ore. - The Oregon Department of Geology and the National Weather Service issued warnings about landslides and flooding on Wednesday - just as two landslides took place on the Oregon Coast.

"Increased potential for landslides and debris flows in northwestern Oregon," the geology department said in a news release Wednesday afternoon.  "A Flood Watch has been issued by the National Weather Service from Wednesday night through Thursday evening for northwest Oregon and southwest Washington."

At almost the same time the press release was received, KATU News learned of two landslides, one in Astoria and another near Manzanita.

The landslide in Astoria prompted the evacuation of three homes on Duane Street and was pushing up against another home, according to witness John Meiners. He said the side of a hill was sliding down near the homes.

The other landslide was located on Highway 101 on Neahkahnie mountain near the coastal town of Manzanita. One lane of Highway 101 was reportedly blocked. No other details were immediately available.

"Debris flows are rapidly moving landslides that can destroy everything in their paths," the Oregon Department of Geology's press release stated. "They can easily travel a mile or more, depending on the terrain. They will contain boulders and logs and transport those in a fast-moving soil and water slurry."


Full text of the Oregon Department of Geology press release:

Increased potential for landslides and debris flows in northwestern Oregon A Flood Watch has been issued by the National Weather Service from Wednesday night through Thursday evening for northwest Oregon and southwest Washington. The official statement from the NWS can be found here.

Flood watch for rivers in northwest Oregon and Southwest Washington draining the Coast Range and Willapa Hills Wednesday night through Thursday night.

The target area includes:

  • Central Coast Range of Western Oregon
  • Central Oregon Coast
  • Central Willamette Valley
  • Coast Range of Northwest Oregon
  • Greater Portland Metro Area
  • North Oregon Coast
  • South Willamette Valley

You should monitor later forecasts and be alert for possible flood warnings. Those living in areas prone to flooding should be prepared to take action should flooding develop.

Care should be taken when traveling over the mountains during this time. The most dangerous places include:

  • Canyon bottoms, stream channels, and areas of rock and soil accumulation at the outlets of canyons;
  • Bases of steep hillsides;
  • Road cuts or other areas where slopes of hills have been excavated or over steepened;
  • Places where slides or debris flows have occurred in the past.

Debris flows are rapidly moving landslides that can destroy everything in their paths. They can easily travel a mile or more, depending on the terrain. They will contain boulders and logs and transport those in a fast-moving soil and water slurry.

Some areas are more hazardous than others when the danger of landslides is high. If there is a flood warning, stay away from the river. Stay away from steep slopes during intense rainstorms. Knowing ahead of time where the danger areas around your home for potential landslides might be is the first step in being prepared.

Follow these steps:

  • Stay alert. Listen to the radio, TV, or a weather radio for flood watches, which include the potential for debris flows and if told to evacuate, do so immediately;
  • Listen for unusual sounds that 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;
  • If water in a river or stream 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;
  • Assume highways are not safe. Be alert when driving, especially at night. Don't overdrive your headlights. Embankments along roadsides may fail, sending rock and debris onto the road;
  • Landowners and road managers should check road drainage systems and conduct needed maintenance in case the predicted heavy precipitation does occur.

Cleaning up after landslides can also be hazardous. "When it is wet outside, be careful when cleaning up the mess. A small mudslide can actually be part of a larger landslide. Cleanup should not be done until after the storm."