A strong atmospheric river moved over Wyoming and brought a prolonged snow that brought heavy snow to much of western and northern Wyoming. Favorable upslope flow in the Tetons resulted in very heavy snow with several reports over 2 feet of snow.
Every event with a place to put it; 7 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 RIW wrote it up.
A strong atmospheric river moved over Wyoming and brought a prolonged snow that brought heavy snow to much of western and northern Wyoming. Favorable upslope flow in the Tetons resulted in very heavy snow with several reports over 2 feet of snow. The top of the Jackson Hole Ski Resort received 55 inches of new snow. Northern portions of the Jackson valley picked up significant snow, but lesser amounts fell in southern portions where there was some mixing with rain. The Salt and Wyoming Range saw as much as 40 inches of new snow, with the nearby Star Valley receiving anywhere from 10 to 16 inches of news now. Over 20 inches of new snow fell in Yellowstone Park and the Absarokas as well. East of the Divide, heavy snow was limited to areas north of a Cody to Greybull line, with almost 11 inches falling to the west of Cody.
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 Riverton, WY wrote its last area forecast discussion before the first event at Feb 15, 9:51 PM MST, 4 hours 9 minutes earlier. Its key messages:
Area Forecast Discussion National Weather Service Riverton WY 951 PM MST Sat Feb 15 2025 .KEY MESSAGES... - The next system arrives tonight, bringing moderate to heavy snowfall across western Wyoming and the Bighorn Mountains through the beginning of the week. Travel impacts expected, especially across western mountain passes. - Lighter snow chances will return to other areas through Tuesday. The best chance for travel impacts east of the Continental Divide will be across northern Wyoming. && .DISCUSSION... Issued at 421 PM MST Sat Feb 15 2025 Light snow is lingering across the area today as the previous system departs. Any additional accumulation through the daylight hours will be minor. Otherwise, temperatures are colder today behind yesterday's front, with highs generally peaking in the 20s east of the Divide. The gusty wind across southern Wyoming will continue through the afternoon, subsiding after sunset. The next system is quickly approaching within the northwesterly flow. This will bring a surge of moisture to the area with snow beginning tonight across western Wyoming after 06Z. With persistent Pacific moisture and jet support, this will be a much more prolonged event than the last one. Snow will become heavier after sunrise Sunday, remaining steady through Sunday night before decreasing somewhat on Monday. Winter highlights have now been issued for much of western Wyoming through Monday night. These may need extended through Tuesday as there will be little change in the setup through then. Lastly, the western Bighorn Mountains will also be participating in this event, though totals there will be lower - in the advisory range for the most part. As usual with west or northwest flow setups with no accompanying low, the remainder of the area will not be as favored for snow. There will be plenty of chances for at least light accumulation, though, especially across northern Wyoming. A nearly stationary frontal boundary will set up from northwest to southeast across southern Montana by Sunday. This feature, combined with a favorable northwesterly/westerly upsloping flow and decent upper jet support, will support periods of heavier snowfall for northern and eastern portions of the Bighorn Basin, especially toward the end of the event on Monday evening as the front finally starts to drop south. These areas will likely need a Winter Weather Advisory, but given that the best chance of higher rates may not come until Sunday night or Monday, we will wait on this for now. Northern Johnson County may also join in on this particular feature with this event, though uncertainty on amounts is higher there. Elsewhere, southern areas (including Sweetwater County) will see their best chances on Sunday with the initial Pacific moisture surge. Forecast accumulations here for Sunday are currently around an inch, but this may need to be watched for the potential for a little more (the greater Rock Springs area currently has around a 55% chance to see at least two inches). This will not be a particularly cold system, and highs across central and southern Wyoming will reach the 30s both Sunday and Monday. The front will drop south on Tuesday, making for a colder day east of the Divide with continued lighter snow. After milder temperatures return midweek, guidance is hinting at the next system arriving sometime in the Wednesday to Friday timeframe. However, there is quite a lot of spread in solutions for this at the moment, and any potential impacts are unclear. && .AVIATION /06Z TAFS THROUGH 06Z MONDAY/... Issued at 950 PM MST Sat Feb 15 2025 West of the Divide...KBPI/KJAC/KPNA/KRKS Terminals. The next winter storm begins to move in to start the TAF period. At JAC, hi-res models start to push in impactful (lowering flight categories chances) around 07z, with the main push of snow coming in between 09z and 11z. Visibilities will largely be half a mile to a mile through much of the period starting between 12z and 14z; have opted for 1 mile in the TAF, with about a 60% chance of prevailing conditions around half a mile. Conditions may begin to improve after 01z/Mon, but confidence is low at this range. At RKS, the best snow chances hold off until about 17z. There are indications that some snow showers may bring rapid decreases in visibilities along with gusty winds. These chances are through the entire afternoon. Have included a prevailing snow group, but there could be periods where snow is not falling. East of the Divide...KCOD/KCPR/KLND/KRIW/KWRL Terminals. Expecting dry, and VFR, conditions to prevail through the period. There could be a couple exceptions, though. At COD, snow will be occurring over the nearby mountains, and an occasional shower may impact the site through the afternoon. Better snow chances come from the north at the very end of the period, but may need to be pushed back into the next period. CPR may also see an occasional snow shower this afternoon, indicated with a PROB30 group. Please see the Aviation Weather Center and/or CWSU ZDV and ZLC for the latest information on icing and turbulence forecasts. && .RIW WATCHES/WARNINGS/ADVISORIES... Winter Storm Warning from 2 AM Sunday to 5 AM MST Tuesday for WYZ001-002-012-024. Winter Weather Advisory from 5 AM Sunday to 5 AM MST Tuesday for WYZ008-014. Winter Weather Advisory from 2 AM Sunday to 5 AM MST Tuesday for WYZ013-023-025. && DISCUSSION...Myers AVIATION...Wittmann
Hazardous Weather Outlook National Weather Service Riverton WY 323 PM MST Sat Feb 15 2025 WYZ001>020-022>030-161400- Yellowstone National Park-Absaroka Mountains-Cody Foothills- North Bighorn Basin-Southwest Bighorn Basin-Southeast Bighorn Basin- Owl Creek and Bridger Mountains-Bighorn Mountains West- Bighorn Mountains Southeast-Northeast Johnson County- Southeast Johnson County-Teton and Gros Ventre Mountains- Jackson Hole-Wind River Mountains West-Wind River Mountains East- Upper Wind River Basin-Wind River Basin-Lander Foothills- Green Mountains and Rattlesnake Range- Natrona County Lower Elevations-Casper Mountain-Star Valley- Salt River and Wyoming Ranges-Upper Green River Basin Foothills- Upper Green River Basin-South Lincoln County- Rock Springs and Green River-Flaming Gorge-East Sweetwater County- 323 PM MST Sat Feb 15 2025 ...Winter Storm Warnings and Winter Weather Advisories in effect for portions of the area... This Hazardous Weather Outlook is for Western and Central Wyoming. .DAY ONE...This afternoon and tonight. Periods of light snow across the area through the afternoon. Locally strong wind in Sweetwater County. The next winter storm pushes in tonight across western Wyoming. Moderate to heavy snow will begin there before sunrise. .DAYS TWO THROUGH SEVEN...Sunday through Friday. Sunday through Tuesday...Moderate to heavy snow expected for western Wyoming, as well across the Bighorn and Wind River Mountains. Some snow is possible across northern Wyoming but amounts and southern extent remain uncertain at this time. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to Standard Operating Procedures.
The national radar mosaic for the moment the first event began.
7 winter storm. Local standard time, as filed.
Heavy snow fell in southwestern portions of Yellowstone Park, with a maximum of 20 inches at the Lewis Lake Divide SNOTEL site.
Heavy snow fell in portions of the Tetons, especially along the western slopes. The top of the Jackson Hole Ski resort picked up 55 inches of new snow. Other notable amounts included 42 inches at Surprise Meadow and 41 inches at Grand Targhee.
Very heavy snow fell in portions of the Salt and Wyoming Range. At Commissary Ridge, 40 inches of new snow was measured. Numerous other locations received 12 to 20 inches of new snow.
A CocoRaHS observer reported 21 inches of new snow.
Heavy snow fell throughout the Star Valley. The highest snowfall total was 16 inches at Bedford.
Heavy snow fell around Cody with amounts from 8 to 11 inches of new snow. Snowfall amounts dropped sharply to the south of Cody.
Heavy snow fell in northern portions of Big Horn County, with a maximum amount of 8 inches in Cowley.
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, February 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 2026-09-24. Each event’s entry at NCEI: 1231575, 1231581, 1231583, 1231576, 1231582, 1231577, 1231579.