A Pacific cold front and trough moved through Wyoming and brought high wind to portions of central Wyoming.
Every event with a place to put it; 6 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 Pacific cold front and trough moved through Wyoming and brought high wind to portions of central Wyoming.
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 Dec 8, 9:31 PM MST, 3 hours 11 minutes earlier. Its key messages:
Area Forecast Discussion National Weather Service Riverton WY 931 PM MST Mon Dec 8 2025 .KEY MESSAGES... - Persistent moderate snowfall continues across the northwest WY mountains tonight. Snow then continues through Thursday, with greatest amounts (1 to 2 feet) across the Absarokas, Pitchstone Plateau, and near Togwotee Pass. - Strong to high wind is likely (greater than a 90% chance) across much of central and southern Wyoming late Monday night through Tuesday. Strongest winds (60 to 70+ mph) will be along the South Pass to Casper Corridor and along the Absarokas and Wind River Mountains Tuesday morning. - Temperatures will remain 10 to up to 20 degrees above normal across much of the region through Thursday. && .UPDATE... Issued at 205 PM MST Mon Dec 8 2025 There was not much change to the overall forecast with snowfall amounts and winds remaining generally on track. Regarding snowfall amounts, there was an uptick across the Tetons and also across the northern Bighorns with the latest forecast. Given that, have opted to hoist an Advisory for the Bighorns and have upgraded the Watch to a Warning for the Tetons. The combination of wind and snow will be the main concern for both locations, more so than amounts. This will be a long-duration event, with snow lingering well into Thursday (beyond the ending of the hazards), however, winds will decrease by Wednesday late afternoon, as will snowfall rates, hence keeping with the 5 PM Thursday timing for ending the highlights. The other Watch areas (Wind River Mountains and Salt/Wyoming Ranges) will likely see Warning amounts, but given the long-duration of the event (over 48 hours) and the limited travel concerns (no impacts to travel corridors) have opted for Advisories for those zones. Regarding wind, the only notable change from the previous forecast was to add a High Wind Warning for the upper Wind River Basin to include Dubois. This area favors west-northwest flow and as the jet moves through tonight, it is looking likely that they will see gusts around 50 to 60 mph, with locally stronger gusts possible. Notably, latest NAM model indicates a period of 70 to 80kts at 700mb Tuesday late morning into the early afternoon. Though not expecting that to fully mix to the surface, it is significant enough of a signal to warrant the Warning. Winds do not look to be as strong on Wednesday for that area, so have only kept the Warning through Tuesday afternoon, rather than Wednesday afternoon with the other High Wind highlights. && .DISCUSSION... Issued at 306 AM MST Mon Dec 8 2025 Sometimes I think the weather is like a rubber band. Basically, you can have a long stretch of quiet weather, but each day builds up tension in the band. Eventually, it ends up snapping. And this is the case over the next few days. Much of November was very quiet and tranquil weather wise. And we are now in one of the more active periods we have had in a while. And a rather complex one, with most threats including wind and snow. In a bit of a change in format, we will hit each one of these individually followed by a general outlook of aspects of the forecast that are less impactful as well as the weather past Wednesday night. SNOW DISCUSSION...We continue to have some mainly light snow falling over the western mountains as I write this around 2 am. It is beginning to let up in the Tetons, so we will likely expire the advisory around 5 am. There should then be a lull in the snow for around 12 to 24 hours before the next round of snow moves in from north to south as a boundary sags southward and a potent 140 knot jet sags southward toward the area, enhancing upper level divergence. The highest confidence for heavy snow continue to be in the Absarokas where there will be some orographic enhancement to go along with the jet energy. Many locations here have greater than a 9 in 10 chance of a foot of new snow with some of the southern portions of the range having nearly a 1 in 2 chance of 2 feet or more. This, combined with some strong wind, looks to be the most impacted area. So, we have issued a Winter Storm Warning here starting tonight and continuing through Wednesday afternoon. Southern portions of Yellowstone Park also have a greater than 3 out of 5 chance of a foot of new snow, but lesser amounts elsewhere. As a result, we had more questions about a warning here, but with the strong wind we went ahead and issued and also to match up with our neighbors to the north. Northern portions of the Park will likely only see advisory amounts though. Further south there are more questions, as the dynamics are not as favorable here with the jet being further away. Nevertheless, a decent portion of the Tetons, Wind Rivers and Salt and Wyoming Range have at least a 1 in 2 chance of a foot of new snow. I'm not completely convinced yet though. Since the bulk of the snow here would not fall until at least Tuesday, we have elected to go with watches and let future shifts decide between warnings, advisories or even nothing. As for the Bighorns, there is at least a 3 out 4 chance of greater than 6 inches of new snow, but the chance of a foot is generally less than 1 out of 3. Any impactful snow would hold off until Tuesday afternoon or evening, so we still have time to decide on any highlights here. As for the lower elevations, impacts look minimal. Warmer air will try to push into the area, especially on Wednesday. With 700 millibar temperatures expected to rise as high as minus 2 by Wednesday, snow levels may rise as high as 7500 feet, keeping the valleys a rain / snow mix and even all rain at times. Chances of 3 inches of snow or more are basically zero because of this. As for the lower elevations East of the Divide, there could be some light snow in the Big Horn Basin and Johnson County. But, with the warmer air moving in, especially on Wednesday, any accumulation would be negligible. One caveat is that there is still some spread in the details of timing of the periods of heaviest snow. The deterministic runs have a lot of differences as well, with the European much wetter than the GFS for example. WIND DISCUSSION...We are already starting to see some gusty wind develop in places like Casper this morning. There has been a bit of a change in that the jet has moved a bit further north, and this brought some of the strongest wind gusts down a bit. However, we still have a good set up for strong wind much of southern and central Wyoming in the right front quadrant of the jet, a tight pressure gradient and strong winds at 700 millibars. The strongest 700 millibar winds are now down to around 60 to 65 knots as opposed to the 80 knots yesterday, guidance does tend to be a bit bold a few days out. Nevertheless, we still have a very good chance of high wind across much of the area. Much of the southwestern wind corridor from Kemmerer to Rock Springs to Casper has at least a 3 in 4 chance of wind gusts past 55 mph sometime between Monday night and Wednesday night. With this, we have upgraded the High Wind Watch to warning for all of the zones starting at 11 pm tonight. The most prolonged high wind will be across southern Lincoln and Sweetwater County, this includes Interstate 80 as well. In Natrona County, Tuesday looks like the most impactful day with a greater than 4 out of 5 chance of wind gusts past 55 mph. Chances drop a bit on Wednesday, but not enough confidence to drop it for this day. There are two other areas of concern. One is in northern Johnson County, which could see a brief period of high wind Wednesday afternoon as flow turns northwest, with some areas having a greater than 1 in 2 chance of wind gusts past 50 mph. The other is the Upper Wind River Basin, which has a similar set up. Again, this would likely not be until Tuesday, so there is still time to decide. Gusty winds are possible elsewhere, but changes of high wind are 1 out of 4 or less. REST OF THE FORECAST...It will be fairly mild outside of the mountains, with some areas seeing highs into the 40s and even the 50s, especially on Wednesday as flow becomes southwesterly. We are also watching another piece of energy that could bring some precipitation to northern Wyoming later Thursday into Friday. There is a large spread in guidance though so confidence remains rather low. Looking ahead to next weekend, at this point to looks largely dry with a gusty wind and above normal temperatures, but confidence remains rather low. && .AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/... Issued at 930 PM MST Mon Dec 8 2025 VFR conditions to start the period with JAC having low ceilings but VFR. Snow showers for JAC but light in nature overnight with all other TAF sites dry. A rain/snow mix likely at JAC after 15Z due to warmer temperatures after sunrise becoming straight snow after 01Z with nighttime cooling. Minimal chances at COD/WRL/CPR after 19Z carrying only VCSH through 01Z. Otherwise, windy conditions throughout the period remaining elevated overnight. Strongest winds at COD/JAC/RIW up to 30kts with RKS up to 45kts after 17Z remaining elevated overnight into Wednesday as well up to 30-35kts. Other locations will be breezy but less winds up to 18-25kts. Mid level ceilings throughout for all locations remaining VFR except JAC down to MVFR around 1-1.5kft in the late afternoon/early evening timeframe. Please see the Aviation Weather Center and/or CWSU ZDV and ZLC for the latest information on smoke, icing, and turbulence forecasts. && .RIW WATCHES/WARNINGS/ADVISORIES... Winter Storm Warning until 5 PM MST Wednesday for WYZ001-002. Winter Weather Advisory from 5 AM Tuesday to 5 PM MST Wednesday for WYZ008-014-015-024. Winter Storm Warning from 5 AM Tuesday to 5 PM MST Wednesday for WYZ012. High Wind Warning until 2 PM MST Tuesday for WYZ016. High Wind Warning until 5 AM MST Thursday for WYZ019-020-022- 027>030. && UPDATE...Hensley DISCUSSION...Hattings AVIATION...Lowe
Hazardous Weather Outlook National Weather Service Riverton WY 315 AM MST Mon Dec 8 2025 WYZ001>020-022>030-091400- 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- 315 AM MST Mon Dec 8 2025 ...Winter Storm Watches and Warnings in effect for most of the western mountains tonight through Wednesday... ...High Wind Warning in effect across southern Wyoming and Natrona County from late tonight through Wednesday night... This Hazardous Weather Outlook is for Western and Central Wyoming. .DAY ONE...Today and Tonight. Mainly light snow in the mountains. Heavier snow moving back into the northern mountains tonight. Please see Winter Weather Products and forecasts for details. Strong to high wind developing from Kemmerer through Rock Springs and into Natrona County. Please see High Wind Warnings for details. .DAYS TWO THROUGH SEVEN...Tuesday through Sunday. Tuesday and Wednesday...Snow likely in the western and northern mountains. Strong to high wind continuing in southern Wyoming. Thursday night and Friday...Another chance for snow in the northern mountains. .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.
6 high wind. Local standard time, as filed.
Numerous locations reported wind gusts past 60 mph. The strongest wind was along Wyoming Boulevard to the south of Casper where gusts up to 71 mph were recorded.
The north face of Casper mountain had 65 to 75 mph gusts reported.
At the Camp Creek and Fales Rock RAWS sites, wind gusts 65 to 75 mph were recorded.
A maximum wind gust of 67 mph was reported at a RAWS site to the southeast of Rock Springs.
Estimated wind gusts of 50 mph blew down a large tree in Rock Springs which destroyed a shed and caused minor damage to the roof of the theatre building.
At the Riverton airport, wind gusted as high as 74 mph. A tree was blown down in a neighborhood near the Riverton high school.
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, December 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: 1306232, 1309299, 1306231, 1306233, 1306234, 1306235.