Snowstorms returning to Pacific Northwest this week (with forecast video)

Plow on snowy road in Washington State.

Snowstorms will soon return to the mountain ranges of the western U.S. But at least every region of the country will be free of widespread disruptive weather for the very early part of the week.


A new round of extended mountain snow/valley rain will develop this week across the Pacific Northwest and southwestern Canada. These won’t be showstopping storms, but brokers, shippers, carriers and drivers should expect periodic delays on the roads, rails, runways and intermodal ramps across the region. Container cargo may also be delayed at ports, along with occasional disruptions to local/regional business operations and supply chains.

SONAR Critical Events and radar on Monday, Jan. 20, 2020, 10 a.m. EST.  Northwest snowstorm threat.

Following a brief break from the weather the past few days, this new series of “on-and-off” storms will begin late tonight. Total new snow accumulations by the end of the week will be 12 to 36 inches in the higher elevations of Washington and Oregon, as well as British Columbia, Canada. In the lower elevations of the region, rainfall totals will be 1 to 3 inches with localized higher amounts. The ground is saturated from periods of heavy rainfall since the new year began. So additional rainfall could result in flooding and mudslides, especially on and near westward-facing slopes in western Oregon, western Washington and British Columbia. Regardless of the precipitation type, drivers may run into roadblocks on portions of I-5, I-84 and I-90.

Other areas of snowfall this week

A burst of heavy snowfall and strong winds will slam the Cascades of northern California tonight and tomorrow. Look for accumulations of 8 to 14 inches in the high elevations including Snowmans, Dead Horse, Etna and Scott Mountain summits, with up to 6 inches along the I-5 corridor from Weed to Mount Shasta. Gusts of 35 to 50 mph will create blowing/drifting snow and reduced visibility at times.

Around the same time, snow will come back to the northern Sierra Nevada. Snow levels on Tuesday will generally remain between 5,500 and 6,000 feet in elevation, with accumulations of 2 to 5 inches possible on northern Sierra passes such as Donner Summit, Echo Summit and Carson Pass. Accumulations near Lake Tahoe level and Mammoth Lakes should be less than an inch. This will be more of a wind maker for the lower valleys, with gusts of 35 to 45 mph across the Tahoe Basin as well as the US-395 and I-580 corridors.

A fairly short-lived storm will come inland tonight and race across the Four Corners region tomorrow, including portions of the Rockies. There will be a decent tap of moisture and the usual orographic lift, leading to several inches of snowfall, especially over the western and northern mountains of New Mexico. Orographic lift occurs when an air mass is forced from a low elevation to a higher elevation as it moves over rising terrain. The upward motion cools the air mass, resulting in condensation – water vapor (a gas) changing to liquid – followed by precipitation. Look for total snow accumulations of 3 to 6 inches above 7,500 feet and 1 to 3 inches below 7,500 feet in the mountains of northern and western New Mexico, possibly affecting some sections of I-25 and I-40.


Carriers with reefers/climate-controlled trailers operating in parts of the Midwest-Great Lakes need to be vigilant regarding “protect from freeze” (PFF) procedures. Following the weekend snowstorm, temperatures will remain frigid the next couple of days, potentially jeopardizing climate-sensitive freight.

SONAR Ticker: Predictive Freeze Index (FREEZE)

Highs will remain at/below freezing in many places such as Chicago; Cleveland; Des Moines, Iowa; Detroit; Fargo, North Dakota; Milwaukee; Minneapolis; Omaha, Nebraska; and Sioux Falls, South Dakota. Lows will be bitterly cold, tonight ranging from 10 degrees below zero to 15 above zero. For some of these cities, these readings are below normal for late January.

Have a great day, and be careful out there!