The Northern Rockies just ran winter and summer in the same week. A rare late-June storm buried the high country of central Idaho, southwest Montana, and the Wyoming border ranges with heavy wet snow, closing two marquee mountain roads before the alerts lifted. NWS Missoula's Winter Storm Warning expired Monday morning, and the NWS Great Falls warning for Northwest Beaverhead County expired at noon, with only light additional snow on the highest peaks after that. Now the pattern flips hard.
The hazard now is not fresh snow but what it left behind: slushy pavement that refreezes overnight on the highest passes, and closures that may not fully lift before holiday traffic arrives. Check Montana 511 and Idaho 511 before you cross anything above 6,500 feet.
What Happened
A slow, cold upper low parked over the region and dropped snow levels to around 6,500 feet just days before July. The heaviest totals stayed on the high terrain:
- Lemhi, Bitterroot, and Sapphire ranges: 4 to 8 inches above 6,500 feet, with as much as 12 inches on the highest peaks.
- Anaconda Pintler near Georgetown Lake: up to 16 inches in the most elevated areas, the storm's local maximum.
- Beartooth Pass and the Yellowstone gateway: 1 to 2 inches along the pass and about 6 inches on the highest terrain, with roughly an inch in Cooke City. An observer at the Top of the World Resort reported about three inches still falling Monday afternoon, with the road slick, icy, and slushy.
The Passes That Closed
The Beartooth Highway on US-212, the All-American Road that tops out near 10,947 feet, closed precautionarily at 4:53 p.m. Sunday in anticipation of the snow and stayed shut through Monday. Inside the park, Dunraven Pass closed Monday morning for winter weather conditions. Crews were working to reopen the Beartooth as early as Tuesday once conditions improved. Farther west, US-93 over Lost Trail Pass near 7,000 feet at the Idaho-Montana line, Chief Joseph Pass on MT-43, Big Hole Pass, Lemhi Pass, and the climb on Idaho 28 all ran wintry through the warning. Confirm current status on Montana 511, Idaho 511, and the Yellowstone road status page before you go. Cowboy State Daily + 2
The Temperature Story
The cold was the headline for most people. Temperatures across western Montana and central Idaho fell 20 to 30 degrees from late-week summer warmth, dropping valley highs into the 40s and 50s, with frost possible in the coldest valleys Monday morning. Wind followed the snow, with gusts to 55 mph on the Beartooth Highway and to 50 mph across the Snake River Plain along Interstate 15, enough to shove high-profile vehicles on exposed stretches.
Driving the Passes This Week
The snow melts fast at these elevations in summer sun, but melt and refreeze is its own trap. A few things worth doing before any high crossing:
- Slow down on bridges, shaded curves, and summit approaches, where slush refreezes first overnight and early in the morning.
- Carry traction devices if you plan to cross a pass that crews are still clearing.
- Keep an honest summer kit in the vehicle: water, a warm layer, and a flashlight go a long way at 7,000 feet.
- Build in extra time and be ready to turn back if a pass is still closed.
What's Next
The flip is dramatic. A heat dome is forecast to expand across roughly 30 central and eastern states from July 2 through 6, pushing temperatures into the 90s and low 100s, and the pattern holds through the holiday weekend. Closer to home, the cooler-than-average start to the week gives way to temperatures in the 80s and low 90s by July 4. Valleys that sat in the 40s and 50s this week will feel like a different season by the time the holiday travel rush peaks. For drivers, the passes should be open and dry for most of that rush, but confirm before you commit to a high route.