Major storms forecast in Oregon’s Cascade Mountains, flash flood watch issued

It could be a wet and wild but very helpful weekend in Oregon’s Cascade Mountains.

Significant thunderstorms dropping a half-inch to 1.5 inches of rain, and bringing winds up to 60 mph, are forecast Saturday afternoon into Sunday morning.

A tenth to a quarter inch of rain will also be possible across the Willamette Valley and foothills.

The storms could be a boon for slowing wildfires and reducing fire danger, especially with a cool and cloudy forecast upcoming. But anyone camping in the mountains could be hammered by wind, rain and possibly lightning.

“Right now we’re about 60-80% sure that the Cascades will see at least a quarter of an inch of rain, and we’re 70% that rainfall will be widespread,” said Daniel Hartsock, a meteorologist at the National Weather Service in Portland. “It just kind of depends where the storms set up. Some places could see 1.5 inches of rain, others could see relatively little.”

In areas where rain is heavier, a flash flood watch has been issued over the wildfire scars of the 2024 fires due to concern over landslides or debris flows, according to the National Weather Service. The rain isn't forecast to be heavy enough to bring landslides in fire scars from previous years, Hartsock said.

“Residents near these areas should prepare for potential flooding impacts,” the NWS alert said. “Be sure to stay up  to date with information from local authorities. Heavy rainfall could trigger flash flooding of low-lying areas, and debris flows in and near recent wildfire burn scars.”

When will Oregon rain arrive?

The rain is forecast to start Saturday afternoon but “really starting to ramp up in the early evening,” Hartsock said. The storms could come and go all night, but should be wrapped up by early Sunday morning.

Where will the rain fall in Oregon?

The heaviest rainfall is forecast for the Cascade Range, all the way from Mount Hood to the Oregon and California border. Slightly less rain is forecast for the foothills and lower elevations, including places such as Oakridge, Detroit, Sweet Home and other mountain communities.

The most likely rain for the Willamette Valley is areas east of Interstate 5, Hartsock said.

Setup for mellowing Oregon wildfires

The weather setup is ideal for stopping or slowing current fires, and reducing fire danger long-term. Many of the fires in the Cascades were already coming into greater containment, and the 1-2 punch of rain followed by cool and cloudy weather next week could slow them in their tracks, Hartsock said.

“As long as we continue with this pattern of onshore flow (from the Pacific), we should be in good shape,” he said. “But there is still a lot of time remaining (in fire season).”

While lightning is forecast to come with some of the storms, any place that sees strikes is likely to be very wet, Hartsock said.

Zach Urness has been an outdoors reporter in Oregon for 16 years and is host of the Explore Oregon Podcast . Urness is the author of “ Best Hikes with Kids: Oregon ” and “ Hiking Southern Oregon .” He can be reached at zurness@StatesmanJournal.com or (503) 399-6801. Find him on X at @ZachsORoutdoors.

This article originally appeared on Salem Statesman Journal: Major storms forecast in Oregon’s Cascade Mountains, flash flood watch issued