It’s the same old song and dance in the northwestern states. More periods of heavy snowfall and whiteout conditions will hit the Cascades of Washington, Oregon and California today and tonight. The Rockies of northern Idaho, western Montana and western Wyoming will also get their fair share. It’s a pattern that started a week ago for many of these areas and could last nearly another week. Total snowfall could exceed 5 feet in some spots before it’s all said and done. The impact of the storms will cross national borders into Canada, affecting travel and freight movement into British Columbia.
Ups and downs
The virtually relentless stream of moisture and energy off the Pacific, called an “atmospheric river” by meteorologists, won’t produce nonstop snowfall for the next several days. It will come in waves. Storms may be quite intense on some days and much weaker on others. Sometimes no snow will be falling. But in between storms, roads will remain treacherous.
It may be risky for drivers who attempt to go over mountain passes in the region, including Stevens, Logan, McKenzie, Marias, MacDonald and Rogers, as well as Snoqualmie and Lookout on I-90. Carriers with drivers in the Midwest who need to get to the Seattle or Portland markets over the next several days should reroute those drivers to the south if possible.
Weather shouldn’t be a major problem on I-80 through Wyoming over to Salt Lake City (strong crosswinds today in southeastern Wyoming will mostly affect I-25). From there, drivers can catch I-84 to the Pacific Northwest. Another option could be I-90 to Butte, Montana, then take I-15 into Idaho. Or catch I-86 in Pocatello, which leads to I-84. There won’t be too much interstate snowfall on these routes.
This is mainly an awareness situation. Impact on freight movement on a national level will likely be minimal. However, the storms could have a moderate/major effect on supply chains and business operations at the local and regional levels. The SONAR Critical Events map below shows assets such as Seattle-Tacoma International (ICAO code: SEA) and Portland International (ICAO code: PDX) airports, oil/petroleum facilities and the ports of Seattle, Tacoma and Portland are at risk of disruptions from time to time as the threat of storms remains in the forecast. These assets are color coded based on the anticipated level of disruption.
The good with the bad
The threat for more heavy rainfall in the foothills and valleys of the Cascades, as well as along and west of the I-5 corridor, is fading. However, rainfall over the past couple of weeks and days has increased soil moisture to high levels across western Washington state. This will put extra pressure on soil instability and could trigger additional landslides the next couple of days.
According to the National Weather Service office in Seattle, as many as six landslides/mudslides have already been reported recently in western Washington, including in Grays Harbor County, where sections of state route 109 remain closed. Grays Harbor County is on Washington’s northwestern coast.
Other areas of snowfall today
Snowfall and strong winds will reduce visibility at times on I-81, I-86 and I-90 in portions of the Northeast and Midwest. This will slow down drivers in Michigan’s Upper Peninsula, as well as northern lower Michigan. Parts of Pennsylvania, upstate New York and New England will not only be prone to lake-effect snowfall but also quick bursts of wind and heavy snow known as “snow squalls.”
Additional notes
Ice accumulation, damaging winds and snowfall of 6 inches or more could hit parts of the Midwest and Great Lakes states this weekend. Exact track and intensity of the storm are difficult to pinpoint right now, but Chicago could end up in the target zone, which is highlighted in the Critical Events map directly above.
There’s potential for flash flooding and thunderstorms across the South late Friday through Saturday. Severe winds and some tornadoes may develop from eastern sections of Texas and Oklahoma to Tennessee and Alabama. The Storm Prediction Center (SPC) has issued an enhanced risk for severe storms on Friday from eastern Texas to the Arklatex area, in addition to parts of central and southern Louisiana. On a scale of 1 to 5, with 5 being the highest risk, enhanced risk is a 3.
This Friday could be the start of a prolonged period of colder than normal weather across parts of the Dakotas and upper Midwest. For carriers running reefers, prepare for elevated protect-from-freeze (PFF) requirements to make sure temperature-sensitive cargo doesn’t spoil. Look for persistent subzero lows — as cold as the negative teens — with highs only in the single digits and teens most days for next week or so. This would include places like Minneapolis-St. Paul, Fargo, Grand Forks, Bismarck, Pierre and Sioux Falls on the I-29, I-90 and I-94 corridors.
Have a great day and be careful out there.