A late-season storm could dump 12 inches of snow or more in parts of Montana and Idaho beginning later Wednesday. Drivers should be prepared to chain up.

Related: States with the strictest chain laws

Regarding tractor-trailers, the Montana and Idaho Departments of Transportation (DOTs) don’t require drivers to use chains every time it snows.

The Montana DOT website says, “Tire chains may be required at any time, anywhere in the state of Montana. They are required on the mountain passes when the chain-up sign is posted.”

The Idaho DOT website says, “Chains are only required when conditions will prevent large vehicles from traversing grades without them, and the requirement is lifted as soon as possible to limit damage to the road. Operators with the Idaho Transportation Department activate special roadside signs alerting truck drivers to chain up as needed during the winter.”


The impending storm will kick in later Wednesday, lasting until Friday morning. Up to 20 inches of snow could pile up in high elevations of the Rocky Mountain Front in western Montana. This includes places like Marias and Logan passes, impacting U.S. highways 2 and 89.

Rogers Pass on Montana highway 200 could see about 15 inches of accumulation, with up to 10 inches possible around McDonald Pass, as well as the mountains near Butte and Missoula.

Look for a few inches in Great Falls, with up to 6 inches in the surrounding mountains, while 3 to 6 inches could pile up in Cut Bank.


The heaviest snow in Idaho will hit the Clearwater Mountains in the panhandle, which could see almost 12 inches in some spots. Lesser amounts, up to 4 inches, will hit Lemhi County in eastern Idaho.

Travel impacts

Besides U.S. and state highways, this storm will slow down drivers on parts of Interstates 15 and 90. The heavy, wet snow will make roads quite slick, with areas of snow and slush refreezing at night. Bridges and overpasses will be most treacherous.

The weight of the snow may bring down electrical lines and tree limbs, leading to scattered power outages and roadblocks.

Farmers with newborn or young livestock could be extremely impacted due to the duration of wet conditions and cold temperatures.

Freight impacts

This snowstorm could delay truckers hauling from the Midwest to the Mountain Prairie and Northwest regions.

(Map: FreightWaves SONAR Headhaul index. To learn more about FreightWaves SONAR, click here.)

The latest FreightWaves SONAR data shows higher outbound volumes compared to inbound in the Midwest region, indicated by the blue shading on the Headhaul Index map above. Red indicates where inbound volumes outweigh outbound, leading to loose capacity.

Click here for more FreightWaves articles by Nick Austin.

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