A winter storm warning has been issued for Oregon’s Cascade Mountain passes, while snow is also expected in the foothills and Coast Range from Sunday to Monday, likely making travel challenging.

Mountain snow is expected to continue Tuesday and Wednesday before heavy rain could lead to flooding later in the week, according to the National Weather Service in Portland.

Heaviest snow on Cascade passes

10 to 30 inches of snow is forecast at the highest Cascade Range passes, including Santiam Pass (Highway 20), Willamette Pass (Highway 58) and the Government Camp area on Mount Hood (Highway 26/35).

The storm warning applies from 10 a.m. Sunday to 10 p.m. Monday. Wind gusts of up to 45 km/h may occur.

“Travel can be very difficult,” the National Weather Service wrote. “Snow blowing snow can significantly reduce visibility.”

Above the passes, at polls above 5,000 feet in elevation, at places like Timberline Lodge, 10 to 4 feet of snow is possible.

Another 4 to 10 centimeters of snow looks possible on the passes on Tuesday.

Snow is also impacting Cascade Foothills, Coast Range

Snow is also possible on lower elevation roads in the Cascade Foothills and Coast Range Sunday evening through Monday.

A winter weather advisory for the Coast Range — which affects roads between the Willamette Valley and the coast — calls for two inches of wet snow above 7,000 feet, and 11 inches above 8,500 feet.

The advice applies from Sunday 4:00 PM to Monday 10:00 PM.

In the Cascade Foothills, near locations such as Marion Forks, 2 to 8 inches of snow is forecast above 2,000 feet, while 5 inches of snow is forecast above 8,000 feet.

Possible flooding later in the week

In addition to steady precipitation in western Oregon early in the week, heavier rain beginning Tuesday evening and lasting through Friday could cause some flooding, NWS said in a hydrological alert.

Current forecasts predict 5 to 8 inches of rain for the Coast, Coast Range and Cascades, with 2.5 to 4 inches for locations in the inland valleys, including Portland, Salem and Eugene, according to NWS.

“Rivers will rise beginning Wednesday. Small streams and fast-reacting rivers may flood as early as Wednesday night or Thursday, while slow-reacting rivers may flood this weekend,” NWS wrote.

“Heavy rainfall will also cause ponding in low-lying areas and other areas with poor drainage.”

Snow levels are expected to remain quite high and rise above snowline levels by Wednesday and Thursday.

Zach Urness has been an outdoors reporter in Oregon for 16 years and hosts the Explore Oregon Podcast. To support his work, subscribe to the Statesman Journal. Urness is the author of “Best Hikes with Kids: Oregon” and “Hiking Southern Oregon.” He can be reached at [email protected] or (503) 399-6801. Find him on Twitter at @ZachsORoutdoors.

This article originally appeared in Salem Statesman Journal: Winter storm warning issued for mountain passes and roads in Oregon