Enormous Supply of Mountain Snow and Valley Rain for the Northwest
Ample tropical moisture will continue to usher in mountain snow and valley rain to the Northwest through the midpoint of the week.
A potent atmospheric river will bring plenty of moisture and ultimately snow to northern California, portions of the Pacific Northwest and the Upper Rockies through Wednesday night. Areas of note include the Pacific Coast Range in northern California, the Sierra Nevada, the Columbia Plateau in Oregon, the Cascades in southern Oregon, Blue Mountains, and the Klamath Mountains. Snow amounts of 2 to 4 feet will occur for the Sierra Nevada, Klamath Mountains and the Pacific Coast Range in northern California after combining this weekend’s snow totals. Five to 10 inches will fall along the Cascades and Blue Mountains in Oregon while lower elevations in Oregon and Washington will see an additional 2 to 5 inches.
This mountain snow activity will also occur across portions of the Upper Rockies. Two to 4 feet of snow is also expected for the Rockies in Idaho through Wednesday night after combining this weekend’s totals. Six to 12 inches will occur through Wednesday night in western Montana, western Wyoming and the Wasatch Range, but isolated amounts of 1 to 2 feet may occur amongst the higher elevations. Lower elevations in northern Idaho will see 3 to 6 inches of snow while north-central and northeastern Montana will see 2 to 5 inches.
Winter Storm Warnings, Winter Weather Advisories, and Winter Storm Watches remain in effect from central and northern California into southeastern Washington, as well as for the Salmon River Mountains and Bitterroot Range in Idaho, and across much of Montana. This includes Mount Shasta and South Lake Tahoe, Calif., Cave Junction, Crater Lake and La Grande, Ore., Walla Walla and Spokane, Wash., McCall, Stanley, and Lowell, Idaho, and Glasgow, Eureka, Great Falls and Missoula, Mont.
Heavy rain will be yet another hazard associated with this atmospheric river event. Portions of central and northern California have Flood Watches in effect, particularly in the Sacramento Valley. This includes Stockton, San Francisco, Sacramento, Redding, Modesto, and Paradise, Calif. Some isolated areas also have Flood Warnings in place, including Corning, Calif. One to 3 inches of rain will douse these locations through Wednesday while the Sierra Foothills will see as high as 6 to 8 inches of rain!
Being aware of travel conditions will be impeccably important as heavy rain can cause dangerous scenarios. Urban and flash flooding, especially in low-lying, flood-prone areas, will be possible. River, stream and creek flooding may also occur due to excess runoff. Mud and rockslides will be possible in the foothills and mountains as well.
The next round of this wintry mess of weather will hit the same areas again Thursday and Friday. Even more mountainous snow and valley rain can be expected.
