NWS Warns of Substantial Precipitation, Possible Debris Flow

The National Weather Service has issued a winter storm warning for Washington and Sherman passes.

Starting Tuesday and continuing through Thursday, the higher mountain passes will be deluged. A rain-snow mix is likely for Stevens and Lookout passes.

The weekend will bring further precipitation and mountain snow.

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What's in store for the Wenatchee area? Forecaster Steve Bodnar has the scoop.

"What you'll see is a fairly robust weather system coming in with a lot of precipitation," Bodnar says. "Overall, the amount of liquid coming with this system is going to be around a quarter-inch, maybe a tenth of an inch in Wenatchee proper. But once you get out of Wenatchee proper, you're looking at half an inch to an inch, with some areas up on the Cascade Crest closer to about two inches."

"That's the liquid equivalent. As far as the precip type, once you get above 4,000 to 5,000 feet, that's going to be primarily snow. Our higher passes, such as Washington Pass on Hwy 20, have the capability to produce two feet of snow."

"Down at Stevens Pass, it'll be more uncertain; there may be some variations between rain and snow at different times." Bodnar anticipates two to four inches, but "some of that will fall as rain and some will fall as snow." There's a slight chance of six or more inches at Stevens Pass, Bodnar says.

Debris flows are possible on steep slopes and near burn scars.

"The burn scars of most concern are the more recent ones that happened here in 2024 - especially ones that are on steep terrain." One such example is the Pioneer Fire burn scar at the top of Lake Chelan. Travel impacts will be minimal except for those in the Stehekin area.

"But the slopes are pretty steep, even along Hwy 97 there, so we could have some small rocks of different varieties coming down - especially if we fall closer to a half-inch or more of rain."

Another potential impact is minor ponding of water. It'll be most acute in low-lying urban areas.

"I'd say the Wenatchee area won't have an issue with that," Bodnar says. "You're only looking at a quarter-inch at most."

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