Flooding, landslides possible through weekend

Nov. 11, 2021 — Oregon’s Office of Emergency Management advises residents to be aware — and prepared — for potential hazards due to heavy rains forecasted this week across the state.

According to the National Weather Service, expected rainfall amounts through Friday may cause potential flooding of creeks and rivers in northwest Oregon, especially along the coastal terrain and Cascades. Rain amounts may be high enough to cause flooding.

Heavy rain can trigger debris flows and landslides in steep terrain, and the risk is higher in wildfire burn areas.

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. 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.

The public can remain safe using basic preparedness actions, including staying informed, being aware of surroundings, having a plan for emergencies and being prepared with an emergency kit.

Stay informed

• Monitor the weather forecast for watches, warnings or advisories at www.weather.gov.
• Sign up for local emergency alerts at oralert.gov.
• If told to evacuate, do so immediately.

Drive with caution

• Be aware of the latest road conditions before driving by checking tripcheck.com.
• Be alert when driving; embankments along roadsides may fail, sending rock and debris onto the road.
• Turn on lights, increase following distance and slow down.
• Don’t drive through flood water; just 6 inches of fast-moving flood water can knock over an adult, and a foot of rushing water can carry away most cars.
• Heed flood watches and warnings
• Beware of hydroplaning. That’s what occurs when your tires are getting more traction on the layer of water on the road than on the road itself — the result is that your car begins to slide uncontrollably. If you start to hydroplane, let off the accelerator slowly and steer straight until you regain control.

Be alert

• A Flood Advisory is issued when a specific weather event that is forecast to occur may become a nuisance: Be aware.
• A Flood Watch is issued when conditions are favorable for flooding to occur: Be prepared.
• A Flood Warning is issued when flooding is imminent or already occurring: Take action.

If your home, work, or route is in a watch area:

• Track the flood watch by radio, TV, weather radio or online. If told to evacuate, do so immediately.
• 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.

Know the signs of landslides

• Look for changes in landscape like leaning trees, land movement, or a trickle of falling mud or debris.
• Pay attention if the water in streams or creeks suddenly turns muddy or the water flow suddenly decreases or increases.
• Listen for unusual sounds, such as trees cracking or boulders knocking together, that might indicate moving debris.

For more information about flood risk and mitigation, visit www.ready.gov/floods. For information on landslides and debris flow, visit www.ready.gov/landslides-debris-flow. For information on flood insurance, visit www.floodsmart.gov.