Low pressure moved across central Wyoming and brought heavy snow to much of northern and central Wyoming. The highest amount recorded was 24 inches at the Hogadon Basin Ski Area.
Every event with a place to put it; 14 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.
Low pressure moved across central Wyoming and brought heavy snow to much of northern and central Wyoming. The highest amount recorded was 24 inches at the Hogadon Basin Ski Area. In the lower elevations, the highest snowfall amounts occurred in the favored easterly to northeasterly upslope flow locations. Amounts around Lander ranged from 8 to 14 inches, with 6 to 12 inches in much of Johnson County and around Casper. The snow brought widespread transportation problems with numerous road closures at the height of the storm.
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 Mar 5, 9:35 PM MST, 3 hours 25 minutes earlier. Its key messages:
Area Forecast Discussion National Weather Service Riverton WY 935 PM MST Wed Mar 5 2025 .KEY MESSAGES... - A large moisture-laden weather system is poised to impact Wyoming Wednesday night through Friday morning. This will bring widespread substantial accumulating snow to the area and is likely (70%) to be the most impactful winter storm of this winter for many locations. Moderate impacts are likely across most of central WY. Some areas across southern and south- central Wyoming could see rain or a rain-snow mix before turning to all snow late Thursday. - Winter Storm Warnings and Winter Weather Advisories are in effect for nearly all of western and central Wyoming, starting overnight and going through early Friday morning. - Most snow will end Friday morning and it will remain cool through Saturday, especially where snow falls with the Thursday weather system. - A warmup will occur Sunday and Monday as high pressure develops across the region. - The next weather system is possible (50%) to move into the area Tuesday night into Wednesday, with the best chances of precipitation across western and southwest Wyoming. && .UPDATE... Issued at 115 PM MST Wed Mar 5 2025 The forecast remains on track for a significant winter storm to impact western and central Wyoming from tonight into Friday morning. Latest forecast shows some minor adjustments, but the winter storm warnings and winter weather advisories remain in effect. Opted to adjust snow ratios slightly downward for the daytime hours Thursday given the time of year and the just below freezing temperatures for parts of central and southern WY. While models and NWS national centers are showing high confidence in the evolution of the storms, personally feel that there are some interesting caveats that could impacts localized precipitation/snow amounts. One of these is the northward extent of the warm air across southern WY and the placement of the surface to low-level boundary. Another is the impact of downsloping in several locations, including the north side of the Uintas into Sweetwater County, and then the western sides of the Wind Rivers and Bighorns with the northeasterly boundary layer flow. The strength of the upslope flow and precipitation rates across parts of central WY could be quite impressive too. As the trough axis moves southeast later Thursday, the surface pressure gradient will shift and allow the colder northern air to move south and east, overcoming the warmer air across southern WY. The latest models are showing that some interesting snow banding could occur across parts of southwest and southern WY Thursday evening into Friday morning, which in turn would heighten impacts in localized areas. Coordination has gone well with surrounding NWS offices and WYDOT. Be safe if traveling over the next couple of days. && .DISCUSSION... Issued at 125 AM MST Wed Mar 5 2025 A transient ridge is sliding into the region this morning. This ridge will bring a slight warmup today before a more potent and large weather system moves in Wednesday night. Model guidance has been consistent with a large trough/upper-low digging into the Central Rockies once it comes onshore Wednesday. On the east side of this trough, synoptic dynamics appear to come together nicely with a strong jet streak, PVA, and WAA over much of Wyoming. There are several variables to break down with this weather system and the details are still being hammered out. Firstly, model guidance depicts several upper-lows breaking off as this system approaches Wyoming. One dives south into the Desert Southwest as another tracks right over southern Wyoming. This is one limiting factor on the intensity of precipitation, although the most recent model runs have been depicting a stronger northern low over Wyoming. Initially, the weather system was projected to move through Wyoming quickly, which would limit total precipitation amounts, but now it is trending slower. Right now the best dynamics look to setup late Wednesday night through Thursday afternoon when the left-exit region of the jet aligns with good PVA. Another factor to pay attention to is how warm the ground is and with a March sun angle this could prove crucial to determining how much snow accumulates during the day on Thursday. What favors high snowfall rates and moderate to high snow totals is the amount of moisture this weather system is bringing with it. PWAT's are forecasted to surge up to 0.5" Wednesday night and remain steady through Thursday afternoon. For reference, this would be at record levels for early March. Wind may also be a factor on Thursday with gusts of 20-30 mph leading to patchy blowing and drifting snow, although this will be somewhat limited by temperatures right around freezing. Have upgraded the Winter Storm Watches to Warnings and issued Winter Weather Advisories where snow amounts/impacts will be moderate. The most favored locations appear to be central basins and easterly upslope favorable areas. Impacts are likely (70%) for I-80 through southern Wyoming, but warmer air should limit snowfall totals from Southern Lincoln County through Sweetwater County. The current forecast, which has been increasing for the past 24 hours is for at least a couple of inches of snowfall with this system and most locations receiving 6 to 10 inches. The Lander Foothills down to South Pass and over into Natrona/Johnson Counties is the bullseye for the highest snowfall amounts of 8 to 16 inches. With an upper-low moving though southern or central Wyoming it is certainly possible a meso-low could develop in the Wind River Basin, which would result in locally higher snowfall amounts there. By Friday morning snow will be winding down, but light snow will linger until Friday afternoon. A large ridge will be right on the heels of the Thursday weather system. Where heavy snow falls and considerable snowpack exists it will remain cool through Saturday, but the clear skies and March sun angle should make quick work of the wet snow. By Sunday, temperatures should rise back to above normal values for most of the area. && .AVIATION /06Z TAFS THROUGH 06Z FRIDAY/... Issued at 935 PM MST Wed Mar 5 2025 West of the Divide...KBPI/KJAC/KPNA/KRKS Terminals. All sites will be transitioning to MVFR or lower during the next couple hours as the significant winter storm arrives. Expect vis to quickly drop to 1SM or less, and remaining low through most of the next 24 hours. Once snow starts to fall, cigs will fall to around 1000 feet and stay through at least 00Z/07. The exception will be KRKS, which remains just far enough from the storm to remain VFR to MVFR through most of the day Thursday. Light snow will fall at times, but will be brief through 00Z/07. Winds will be the main concern, as gusty winds will vary from 110 to 190 degrees through the afternoon. As the storm wraps east, the snowfall will increase at KRKS, currently expected around 00Z and continuing into Thursday evening. Still some uncertainty here on timing and strength. East of the Divide...KCOD/KCPR/KLND/KRIW/KWRL Terminals. Winter storm spreads northeast through the overnight hours, starting by 08Z for KLND/KRIW/KCPR and by 10Z for KCOD/KWRL. Vis and cigs will fall to IFR within 2 hours of the commencement of snowfall, and will likely stay near IFR limits through the remainder of the next 24 hours, with vis 1SM or less and cigs under 1000 feet. KCPR and KRIW will also be impacted by gusty east to northeast winds, with some gusts 20 to 30kts for most of the day. && .RIW WATCHES/WARNINGS/ADVISORIES... Winter Weather Advisory until 2 AM MST Friday for WYZ001-002- 013. Winter Storm Warning from 5 AM Thursday to 5 AM MST Friday for WYZ003-005-007-009>011-020-022. Winter Weather Advisory from 5 AM Thursday to 5 AM MST Friday for WYZ004-006. Winter Storm Warning until 5 AM MST Friday for WYZ012-014- 024>026. Winter Storm Warning until 5 AM MST Friday for WYZ015>019. Winter Weather Advisory until 5 AM MST Friday for WYZ023-027. Winter Weather Advisory from 2 PM Thursday to 5 AM MST Friday for WYZ028>030. && UPDATE...McDonald DISCUSSION...Rowe AVIATION...Straub
Hazardous Weather Outlook National Weather Service Riverton WY 131 AM MST Wed Mar 5 2025 WYZ001>020-022>030-061245- 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- 131 AM MST Wed Mar 5 2025 ...WINTER STORM WARNING IN EFFECT FROM 8 PM THIS EVENING TO 5 AM MST FRIDAY... ...WINTER WEATHER ADVISORY IN EFFECT FROM 8 PM THIS EVENING TO 5 AM MST FRIDAY... ...WINTER STORM WARNING IN EFFECT FROM 11 PM THIS EVENING TO 5 AM MST FRIDAY... ...WINTER WEATHER ADVISORY IN EFFECT FROM 11 PM THIS EVENING TO 2 AM MST FRIDAY... ...WINTER STORM WARNING IN EFFECT FROM 5 AM THURSDAY TO 5 AM MST FRIDAY... ...WINTER WEATHER ADVISORY IN EFFECT FROM 5 AM THURSDAY TO 5 AM MST FRIDAY... ...WINTER WEATHER ADVISORY IN EFFECT FROM 2 PM THURSDAY TO 5 AM MST FRIDAY... This Hazardous Weather Outlook is for Western and Central Wyoming. .DAY ONE...Today and Tonight. Snow moves into southwest Wyoming this evening and spreads northeast overnight. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. Thursday and Friday...A large moisture laden weather system brings widespread accumulating snow to the area. At least minor impacts will be felt across the area, with high impacts for many locations. Greatest areas of concern for heavy snow is across the Wind River Basin, South Pass, and the I-25 Corridor. Tuesday... Chances for snow across western Wyoming as a weather system approaches from the west. .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.
14 winter storm. Local standard time, as filed.
Heavy snow fell through much of the eastern Wind River Range, with a maximum amount of 16 inches at the Townsend Creek SNOTEL site.
At Farson, 6 inches of new snow fell.
Snowfall amounts around Riverton ranged from 7 to 12 inches, including 7.8 inches at the Riverton Weather Forecast Office.
Snowfall amounts ranged from 8 to 16 inches across the Lander Foothills, including 13.5 inches at the Lander airport.
At Jeffrey City, 16 inches of new snow fell.
New snowfall amounts generally ranged from 6 to 12 inches, including 11 inches in Buffalo.
Trained spotters reported 4 to 7 inches around Thermopolis.
Trained spotters reported 12 inches of snow to the west of Kaycee.
In Dubois, 6 inches of new snow fell.
Snowfall amounts in Natrona County ranged from around 6 inches in Midwest to 13 inches on the south side of Casper.
At the Hogadon Ski area, 24 inches of new snow fell.
Any between 5 to 9 inches of snow fell in the Upper Green foothills, including a maximum amount of 9 inches at Boulder.
There were numerous reports of 8 to 11 inches of new snow in the Star Valley, incluiding 9.2 inches at Afton.
At Commisary Ridge, 18 inches of new snow fell. Many SNOTEL sites reported 10 to 18 inches of new snow.
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, March 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: 1235454, 1247687, 1247680, 1247681, 1247682, 1235447, 1235444, 1235450, 1235457, 1247683, 1247684, 1247686, 1247688, 1247685.