Low pressure passing south of Wyoming brought heavy portions to portions of central and southern Wyoming. Two areas saw the heaviest snow.
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.
Low pressure passing south of Wyoming brought heavy portions to portions of central and southern Wyoming. Two areas saw the heaviest snow. The first was in the favored northerly upslope areas from the Wind River Range through Casper Mountain. The heaviest snow fell in the Wind River Range where as much as 22 inches of new snow fell. In the lower elevations, Lander picked up from 10 to 20 inches of snow. A band of snow also set up across Sweetwater County, where 6 to 14 inches of snow fell from Green River to Wamsutter. The heavy snow led to closure of Interstate 80.
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 13, 3:44 AM MST, 2 hours 16 minutes earlier. Its key messages:
Area Forecast Discussion National Weather Service Riverton WY 444 AM MDT Wed Mar 13 2024 .KEY MESSAGES... - Snow will spread across much of the area today, with the heaviest snow expected tonight. - Gusty to strong wind will accompany the snow at times, bringing difficult travel conditions. - Quieter weather returns for Friday, with warming temperatures early next week. && .DISCUSSION... Issued at 233 AM MDT Wed Mar 13 2024 Things look like the are lining up for a decent snowstorm across portions of the area. Things are quiet right now but radar is showing snow loading up in Montana and this will dropping southward into the area through the morning and afternoon as a cold front moves southward through the area. And for the most part, reasoning remains the same as yesterday. We have high confidence in time of maximum impact, medium confidence in timing and low confidence in snowfall amounts, although those huge ranges have shrunk somewhat this morning. The main drivers continue to be the cold front, an upper level low dropping southward from Idaho into the Great Basin and lee cyclogenesis that will occur over Colorado with low pressure moving into the Plains states. The main driver to the location of the snowfall amounts will be the northeasterly upslope flow. The upslope northeast to east flow is fairly deep as well, ranging all the way up to 500 mb. This will result in a good fetch of moisture moving into the area. And places favored by this flow, like Lander and Casper Mountain as well as the east slopes of the Wind River Range look to be the most effected. To a lesser extent this is also for the Bighorns. For the most part, snowfall amounts did not change much. So, we left highlights for the most part as is. There were a couple of things to consider though. The first was the Bighorns, amounts increased somewhat. We thought about warnings but since the areas with those amounts account for less than 10 percent of the area, we stuck with advisories. We thought about an advisory for Johnson County as amounts have increased, However, much of the snow here would fall before 7 pm, aka when the strong March sun is out. This, plus the borderline temperatures and warm ground, should keep roads mainly wet. So, no advisories here as well. A small part of southern Johnson has advisory amounts, but again this accounts for less than 10 percent of the area. In addition, other areas will have borderline temperatures and may mix with rain at times during the day, again, limiting travel impacts somewhat. The maximum impact still looks to be tonight as the snow gets enhanced by a bit of a jet streak rotating into the area. We could see snowfall rates over an inch an hour at times, with the best chance of seeing this from western Natrona through Fremont County as well as Sweetwater County. Models have come into somewhat better agreement in ending the steadier snow Thursday morning. Some snow showers will linger into Thursday night, but placement of these are all over the place. The other concern is wind. The wind will first hit in the favored northwest flow / cold advection areas up north like Buffalo and Greybull. High wind is not expected, but it will get gusty. The stronger wind then shifts southward into central Wyoming tonight. The strongest wind will be across Sweetwater County, especially on Thursday with a tight pressure gradient between high pressure over the Pacific northwest and the deepening low in the southern plains. There is a 1 in 2 chance of wind gusts of 50 mph in this area on Thursday. IF there is one saving thing, it is that the heaviest snow will be over and the snow will be wetter, limiting blowing snow somewhat. It will still not be any fun to travel there on Thursday though. Quieter weather should move in for Friday,although temperatures will average around 10 degrees below normal. The recent model runs have started to keep the potential weekend system east of Wyoming now. We have kept some slight POPs as a hedge, but it does not look like a major system. Dry weather looks to dominate the weather early next week as ridging builds across the northern Rockies. && .AVIATION /12Z TAFS THROUGH 12Z THURSDAY/... Issued at 430 AM MDT Wed Mar 13 2024 West of the Divide...KBPI/KJAC/KPNA/KRKS Terminals VFR conditions to start the period with sporadic light snow throughout the day becoming more consistent on station later by 21-01Z. Breezy north winds 10-15kts after 15Z then gusting up to 25-30 kts behind the cold front after 01Z at RKS. Winds and snow will diminish after the end of the period into the next TAF cycle. Otherwise, MVFR ceilings and visibility with IFR possible at RKS with the stronger winds with snow on stations. East of the Divide...KCOD/KCPR/KLND/KRIW/KWRL Terminals VFR conditions to start the period with lowering clouds and incoming light snow after 15-16Z at all locations. MVFR ceilings and visibility will accompany snow on station with increasing wind gusts out of the north behind the cold front after 23-02Z north to south. Expect improving conditions into the next TAF cycle after 12Z with best model guidance not seeing VFR conditions again until late Thursday morning into the afternoon hours. 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 Weather Advisory until 6 AM MDT Thursday for WYZ008-009. Winter Storm Warning until noon MDT Thursday for WYZ015-019- 022. Winter Weather Advisory from noon today to 6 AM MDT Thursday for WYZ017-020. Winter Storm Warning from noon today to noon MDT Thursday for WYZ018. Winter Weather Advisory from 6 PM this evening to noon MDT Thursday for WYZ028>030. && DISCUSSION...Hattings AVIATION...Lowe
Hazardous Weather Outlook National Weather Service Riverton WY 124 AM MDT Wed Mar 13 2024 WYZ001>020-022>030-141400- 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- 124 AM MDT Wed Mar 13 2024 ...Winter Weather Advisories and Warnings are Posted for much of central and southern Wyoming through Thursday morning as well as the Bighorns... This Hazardous Weather Outlook is for Western and Central Wyoming. .DAY ONE...This Afternoon and Tonight. Snow spreads from north to south across the area, with the heaviest snow tonight in central Wyoming. Gusty north to northeast wind will bring areas of blowing snow after midnight. Please see Winter Weather Products and forecasts for details. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. Thursday...Snow ends from north to south during the morning. Gusty northeast wind continues through the day across Sweetwater County, including I-80, and over South Pass. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to Standard Operating Procedures.
Special Weather Statement National Weather Service Riverton WY 621 AM MDT Wed Mar 13 2024 WYZ010-011-140000- Northeast Johnson County-Southeast Johnson County- Including the cities of Buffalo and Kaycee 621 AM MDT Wed Mar 13 2024 ...Snow returning to the area... This is a special weather statement from the National Weather Service Office in Riverton. * WHAT...Snow. Accumulations of 1 to 2 inches, with locally higher amounts west of Interstate 25. Northwest wind increasing to 15 to 25 mph with gusts to 30 to 40 mph. * WHERE...Johnson County. * WHEN..Into early this evening, with the heaviest snow expected this afternoon. * ADDITIONAL DETAILS...Accumulations will be less on paved surfaces.
The national radar mosaic for the moment the first event began.
6 winter storm. Local standard time, as filed.
Heavy snow fell through much of the eastern slopes of the Wind River Range. The highest snowfall total was 22 inches at the Hobbs Park SNOTEL site.
Heavy snow and drifting snow lead to the closure of Highway 287.
The Casper Mountain SNOTEL reported 18 inches of new snow.
Snowfall amounts ranged from 10 to 20 inches, with the higher amounts toward Sinks Canyon.
Snowfall amounts generally ranged from 6 to 12 inches. The heavy snow led to closure of Interstate 80.
A trained spotter measured 14 inches of snow in Wamsutter. The heavy snow led to closure of Interstate 80.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Wyoming in 2024Every state in 2024This day in weather historyWarnings in Wyoming, March 2024
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: 1168276, 1168277, 1168278, 1168279, 1168280, 1168281.