The same cold front is delivering two different alerts across two states.
Eastern Idaho is under a Frost Advisory. Western Wyoming’s Star Valley is under a Freeze Warning. Both trace back to the same push of cold air moving through the Mountain West.
Eastern Idaho: Frost Advisory for the Snake River Plain
The NWS Pocatello office has a Frost Advisory in effect from 3 AM to 9 AM MDT Tuesday.
Temperatures could drop to 34 degrees across the Shoshone/Lava Beds, Arco/Mud Lake Desert, and the Upper and Lower Snake River Plain.
That covers Idaho Falls, Pocatello, Rexburg and Blackfoot, along with St. Anthony, Shelley, Mud Lake, Carey, Fort Hall, Richfield and Shoshone. Craters of the Moon National Monument and the Idaho National Laboratory site are included too.
Star Valley, Wyoming: Freeze Warning as Temps Drop to 28
The NWS Riverton office has a stronger alert in place: a Freeze Warning from 3 AM to 9 AM MDT Monday.
Temperatures could fall to 28 degrees, mainly across the south half of Star Valley, including Alpine, Afton, Star Valley Ranch and Thayne.
The office flagged the wind threat separately, ahead of the colder air behind it.
BE PREPARED!
Time It Right
The coldest air usually settles in right around sunrise, not at midnight, so there’s no rush to cover everything the moment the sun goes down. Get plants covered before bed, and leave the covers on until temperatures climb back above freezing the next morning. If a hard freeze is expected to follow the frost, go ahead and bring in any tender herbs or vegetables you’d rather not risk losing overnight.
Don’t Forget the Pipes
Outdoor faucets, hoses and irrigation lines are just as exposed as your plants are….
Read full article: Risky Frost and Freeze Warnings Issued for 10 Counties in Wyoming and Idaho as Temperatures Plummet
The post “Risky Frost and Freeze Warnings Issued for 10 Counties in Wyoming and Idaho as Temperatures Plummet” by Luka Trcek was published on 09/14/2026 by www.travelinglifestyle.net