The National Weather Service issued a “Flood Watch” across Oregon at 1:10 a.m. Saturday. 

The report warns of a prolonged atmospheric river likely to bring heavy rainfall starting late Sunday night and ending around late Thursday evening. 

The National Weather Service warns that river and urban flooding as a result of the prolonged atmospheric river is possible. 

The warning pertained to a large part of Oregon’s coast and even some of western Washington, stretching south to the Lane County lowlands and north to the southern Washington coast. 

The watch will be in effect from Dec. 6 to Dec. 11, with eyes especially on the periodic heavy rain expected to hit northwestern Oregon and southwestern Washington from Monday, Dec. 8  to Wednesday, Dec. 10. 

The report warns that due to the expected rainfall, “Excessive runoff may result in flooding of rivers, creeks, streams, and other low-lying and flood-prone locations.”

The report also includes that, among the effects of the heavy rains, landslides and debris flows are most common in areas that have recently been burned or areas close to steep terrain.  

The National Weather Service warns that “People, structures, and roads located below steep slopes, in canyons, and near the mouths of canyons may be at serious risk from rapidly moving landslides.”

According to the report, rivers draining the coastal mountains — including but not limited to the Siuslaw, Umpqua, Yaquina, Alsea, and Tillamook rivers — as well as several Willamette tributaries have a substantial chance of flooding, ranging from 40-70%.

However, the report does assure that the Willamette River carries a slim chance of flooding, that being below 5%. 

“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,” the report states.

Readers curious about resources available in Corvallis can find more information at the Flood Preparedness Brochure, found on the Corvallis.gov website. 

The brochure is updated annually by the city and contains information on flood insurance, backwater protection, flood preparation, the city’s own flood response plan and more.