A Winter Rainstorm Passing Over Portland Tonight Could Cause Flooding and Landslides in Fire-Scarred Areas

Portland is about to be bombarded with another rainstorm—and this one could bring landslides.

Tonight, another atmospheric river will descend on Portland, bringing heavy rains and flood warnings.

Though we're due for another dumping tonight, Portland saw the worst of the rain last night. The Gorge and the Cascade foothills, however, could see their highest levels of precipitation yet this winter.

Rainstorms aren't exactly unusual winter weather in Oregon, but this particular system will fall heaviest on areas that were recently damaged by fire. That means that landslides are a nail-biting possibility.

"We're pretty concerned about the threat for debris flows and slides," says Andy Bryant, a meteorologist for the National Weather Service. "All of the burnt areas in the Cascade foothills are going to be affected, it's just a matter of, will the rain be heavy enough to cause problems?"

The Cascade foothills—including areas damaged by the Beachie Creek and Riverside fires—have already been subjected to substantial rainfall that hasn't led to widespread problems. But tonight's rain could be heavier than any of the other storms that have passed through the region this winter.

In impact reports released last month, the Natural and Cultural Resources Recovery Task Force declared several areas along Highway 22 "very high risk" for debris flow due to fire damage. The recently reopened Eagle Creek area will also see heavy precipitation and possible erosion damage.

Closer to Portland, Johnson Creek, the Sandy River and the Clackamas River all have flood warnings.

The risk for power outages, however, is low. Winds aren't expected to become strong enough to topple trees and cause downed lines.

"The one caveat to that is, with the ground so saturated, if there's a tree that's on the weak side, it might blow over," says Bryant. "But I think those types of incidents will be isolated."

The heaviest rain is forecast to fall overnight and let up tomorrow morning. For the rest of the week, Portlanders will only have to deal with much gentler rainfall.