An early mountain snow event began late on September 22nd and lasted through the afternoon of September 23rd. High elevation mountain passes over 9000 feet were mostly impacted with snow covered roads and slushy and slick conditions.
Every event with a place to put it; 1 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS CYS wrote it up.
An early mountain snow event began late on September 22nd and lasted through the afternoon of September 23rd. High elevation mountain passes over 9000 feet were mostly impacted with snow covered roads and slushy and slick conditions.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Cheyenne, WY wrote its last area forecast discussion before the first event at Sep 22, 10:45 PM MST, 45 minutes earlier.
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</html>Hazardous Weather Outlook National Weather Service Cheyenne WY 321 PM MDT Mon Sep 22 2025 NEZ002-003-019>021-054-055-095-096-WYZ101>119-232130- Dawes County-Box Butte County-Scotts Bluff County-Banner County- Morrill County-Kimball County-Cheyenne County- Northern Sioux County-Southern Sioux County- Converse County Lower Elevations-Niobrara County- North Laramie Range-Ferris/Seminoe/Shirley Mountains- Shirley Basin-Central Laramie Range and Southwest Platte County- East Platte County-Goshen County-Central Carbon County- North Snowy Range Foothills-Southwest Carbon County- Sierra Madre Range-Upper North Platte River Basin-Snowy Range- Laramie Valley-South Laramie Range-South Laramie Range Foothills- Central Laramie County-East Laramie County- 321 PM MDT Mon Sep 22 2025 This hazardous weather outlook is for portions of panhandle Nebraska...east central Wyoming...south central Wyoming and southeast Wyoming. .DAY ONE...THIS AFTERNOON AND TONIGHT - A cold front and Pacific storm system will bring much cooler temperatures and unsettled weather Monday night and Tuesday. Mountain snowfall is expected above 8500 feet. .DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY - A ridge of high pressure aloft will lead to drier and warmer weather for Thursday through the weekend. .Spotter information statement... Spotter activation will not be needed.
Special Weather Statement
National Weather Service Cheyenne WY
728 PM MDT Mon Sep 22 2025
NEZ002-230200-
Dawes NE-
728 PM MDT Mon Sep 22 2025
...A STRONG THUNDERSTORM WILL IMPACT EAST CENTRAL DAWES COUNTY
THROUGH 800 PM MDT...
At 728 PM MDT, Doppler radar was tracking a strong thunderstorm near
Chadron, moving southeast at 15 mph.
HAZARD...Wind gusts up to 40 mph and half inch hail.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects. Minor hail damage to vegetation is
possible.
Locations impacted include...
Chadron, Red Cloud Campground, Chadron State Park, Dawes County
Fairgrounds, and Chadron State Park Campground.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
&&
LAT...LON 4278 10317 4286 10301 4273 10284 4261 10302
TIME...MOT...LOC 0128Z 323DEG 13KT 4277 10302
MAX HAIL SIZE...0.50 IN
MAX WIND GUST...40 MPH
MMThe national radar mosaic for the moment the first event began.
1 winter weather. Local standard time, as filed.
Most SNOTEL sites in the Snowy Range showed between 3 to 5 inches of snow. Sand Lake SNOTEL reported 6 inches of snow fell, which is adjacent to highway 130 Snowy Range Pass.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Wyoming in 2025Every state in 2025This day in weather historyWarnings in Wyoming, September 2025
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-10-01. Each event’s entry at NCEI: 1289377.