Low pressure crossed the state and brought heavy snow and high wind to portions of western and central Wyoming. The heaviest snow fell in the Tetons where up to 16 inches of new snow fell at the Jackson Hole Ski Resort.
Every event with a place to put it; 8 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 crossed the state and brought heavy snow and high wind to portions of western and central Wyoming. The heaviest snow fell in the Tetons where up to 16 inches of new snow fell at the Jackson Hole Ski Resort. The Jackson Valley was also hard hit with 6 to 10 inches of snow. Moderate to heavy snow combined with strong wind as well. Wind gusted as high as 94 mph at Red Canyon along Highway 28, resulting in the closure of Route 28 over South Pass. A wind gust of 76 mph occurred at the top of the Jackson Hole Ski Resort. High wind also occurred in the wind prone areas of central Wyoming, with wind gusts over 70 mph around Casper and 66 mph around Buffalo.
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 9, 9:36 PM MST, 3 hours 24 minutes earlier.
Area Forecast Discussion National Weather Service Riverton WY 936 PM MST Thu Mar 9 2023 .DISCUSSION...(This evening through Thursday) Issued at 151 PM MST Thu Mar 9 2023 Predominant zonal flow along the generally straight jet stream over Wyoming will keep the flow of moisture into the region. The next in the series of shortwaves to impact the region will move into the west this evening and overnight tonight. This shortwave in conjunction with the jet will draw significant moisture into western Wyoming. Up to 2 inches of liquid (SWE) is possible across some of the western mountain locations in 1 to 2 feet of snow. Western valleys will also get a significant amount of snow, however exact amounts are a little trickier there due to warmer surface temperatures. This is one of the warmest systems we've seen so far this winter (it is March, after all) and resulting surface temps will be in the low to middle 30s across Jackson Valley and especially Star Valley Friday afternoon. This will raise snow levels to near 7000 feet, and at the valley level, rain could even mix in with snow at times. The warmer temperatures will help to limit impacts across the valleys, however, mountain passes will not likely be so lucky, meaning travel will be quite hazardous across Teton, Togwotee, and Salt Passes Friday and Friday night. This is not only a result of the heavy snow, but also very strong winds. Winds will increase through the day Friday, with gusts 50 to 60 mph across the mountains by late afternoon. In the valleys, winds will also be gusty with gusts 20 to 30 mph, locally up to 40 mph. The warmer temps during the day will reduce the blowing and drifting snow threat, but not completely eliminate it. Exposed areas could certainly see blowing and drifting snow Friday afternoon through Friday night, despite the heavy, wet nature of the snow. These very strong winds will continue into the overnight hours, diminishing towards sunrise Saturday. Snow will also be possible across the south. The upper Green River Basin and southern Lincoln County could see 3 to 6 inches, with locally higher amounts towards Sage Junction and Cokeville and towards Pinedale and the Bondurant Valley. Sweetwater County will also see some snow, locally up to 1 inch, however, especially towards eastern Sweetwater County, winds will be quite gusty with gusts 30 to 40 mph expected. This could create some travel concerns along I-80, despite otherwise light snowfall amounts. East of the Divide, wind will be the main concern. Flow is not favorable for snow to make it over the Divide and significant downslope flow will not help either. West-southwest 700mb flow will increase to 50 to 60kts by late Friday afternoon, resulting in some quite strong winds across favored areas including South Pass, Jeffrey City, and Casper. The High Wind Watches have been upgraded to Warnings with the afternoon update for the Rattlesnake/Green Mountain and Natrona County zones. Will also need to keep an eye on the Lander Foothills and Cody Foothills for the wind threat, however, flow appears to be too westerly to fully favor Lander for high wind. With the wind, basins that have not previously fully mixed out their cold pools, will likely do so Friday. This includes the Wind River and Bighorn Basins. Temperatures are expected to climb above freezing in those areas. With the strong, warm, downsloping winds, could see a bit of melting of snow/ice Friday. This is a bit of a concern as rivers could see some minor rises as a result, however, temperatures will quickly dip back below freezing overnight so the melting should be short-lived and we are not looking at any flood concerns at this time. This storm will move out of the region Saturday, with both snow and the strong winds diminishing by sunrise and snow ending completely by midday. Ridging will build through the rest of the weekend and into early next week. This means that those colder basin locations may continue to see temps climb above freezing during the day through at least Tuesday with temperatures around 50 possible across the Cody Foothills and Johnson County Monday and especially Tuesday. These temperatures are still 5 to 10 degrees below normal, but it will certainly feel warmer than we've been all winter. These warmer temps will however increase the flooding concern as several days with highs well above freezing will help to ripen snowpack. Luckily, we are not looking at extended warmth and overnight temps will drop below freezing, limiting the melting. As a result, our flooding concerns will remain low for now. Other than some light snow showers across the far west, the rest of the weekend and into early next week looks pretty dry and quiet overall. Models are progging the next storm for Tuesday/Wednesday. Again, in generally westerly flow, it looks to be a mainly west of the Divide event, but will continue to watch this as we get into the weekend and early part of next week. && .AVIATION...(For the 06Z TAFS through 06Z Friday night) Issued at 936 PM MST Thu Mar 9 2023 West of the Divide...KBPI/KJAC/KPNA/KRKS Terminals. Widespread snow will spread over much of the area except for Sweetwater County between 06Z and 12Z. IFR conditions are expected at KBPI, KJAC and KPNA. High resolution models then show a potential break in snow between 14Z and 18Z especially for KBPI and KPNA. Will show this break in the TAF. Confidence in this occurring at KJAC is less certain so will keep IFR conditions there. If this break does occur, IFR conditions will once again develop by around 18Z. LIFR conditions are likely at those terminals as times, with a decent chance of a prolonged period IFR/LIFR conditions at KJAC. Airfield minimums are expected as well at those terminals, but especially at KJAC at times. The snow over those 3 terminals should end between 02Z and 06Z Saturday. KRKS has the best chance of snow and associated MVFR/IFR conditions between 21Z Friday and 06Z Saturday. VFR conditions are expected to develop at all terminals between 04Z and 08Z Saturday. Windy southerly flow is expected to develop over much of the area between 16Z and 20Z Friday with weakening in the Upper Green River Basin by around 00Z Saturday, but KJAC and KRKS will remain breezy for much of the night. Mountains will be obscured much of the time through at least 03Z Saturday. East of the Divide...KCOD/KCPR/KLND/KRIW/KWRL Terminals. VFR conditions with mainly considerable mid-level cloudiness through 18Z. The exception will be at KCPR where ceilings could lower to around 5 kft agl by around 12Z. Not out of the question for some morning fog, but confidence is not enough to warrant for VCFG at any terminal at the moment. Will have VCSH at KLND beginning around 12Z for the spill over snowfall becoming within around 10 miles west of the terminal. This snow is not expected to reach KLND. The main issue at KLND between 12Z and 18Z will be LLWS as surface winds become light northeast with strong southwest winds just above the surface. The strong southwest winds are expected to mix down to KLND around 18Z. Very strong southwest winds are expected to develop at KCPR between 12Z and 18Z. Gusts to around 45 knots are possible at this terminal. Breezy winds are also expected at the other terminals Friday afternoon, before the winds weaken between 00Z and 06Z Saturday. Scattered snow showers are possible mainly between 21Z Friday and 03Z Saturday especially at KCPR, KLND, and KRIW. Brief MVFR/IFR conditions could occur, but will not prevail these conditions. VFR conditions with decreasing cloudiness after 06Z Saturday. Please see the Aviation Weather Center and/or CWSU ZDV and ZLC for the latest information on icing and turbulence forecasts. && .FIRE WEATHER... Issued at 151 PM MST Thu Mar 9 2023 Significant wet, heavy snow expected beginning tonight across the west and continuing through Friday night. Very strong winds with gusts 50 to 60 mph expected across zones 279/280/289 as well as 286/288 Friday and Friday night. Snow and wind end Saturday. Warmer and mostly dry through the rest of the weekend and into early next week with light snow showers possible across the far west. The next storm system is expected to impact the region Tuesday and Wednesday. && .RIW WATCHES/WARNINGS/ADVISORIES... Winter Storm Warning from 2 AM Friday to 5 AM MST Saturday for WYZ001-012>015-023>025. Winter Weather Advisory from 2 AM Friday to 5 AM MST Saturday for WYZ002-026-027. High Wind Warning from 8 AM Friday to 5 AM MST Saturday for WYZ019-020. && DISCUSSION...Hensley AVIATION...Murrell FIRE WEATHER...Hensley
Hazardous Weather Outlook National Weather Service Riverton WY 111 PM MST Thu Mar 9 2023 WYZ001>020-022>030-110015- Yellowstone National Park-Absaroka Mountains-Cody Foothills- North Big Horn Basin-Southwest Big Horn Basin- Southeast Big Horn 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- 111 PM MST Thu Mar 9 2023 ...Winter Storm Warnings and Winter Weather Advisories in effect for the western mountains and valleys Friday and Friday night... ...High Wind Warning in effect for the Green Mountains and Natrona County Friday and Friday night... This Hazardous Weather Outlook is for Western and Central Wyoming. .DAY ONE...This Afternoon and Tonight. Snow spreading into western Wyoming after midnight. Please see Winter Weather Products and forecasts for details. .DAYS TWO THROUGH SEVEN...Friday through Wednesday. Friday and Friday night...Moderate to heavy snow likely in the western mountains and valleys. Significant accumulations possible. High wind east of the Continental Divide. Creek and river levels may rise with potential for snow melt Friday afternoon. Tuesday...A chance of snow in western Wyoming. .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.
4 winter storm, 3 high wind, 1 heavy snow. Local standard time, as filed.
On top of the Jackson Hole Ski Resort, 16 inches of new snow fell. High wind accompanied the snow, with a maximum wind gust of 76 mph.
Snowfall amounts around the Jackson Valley ranged from 6 to 10 inches.
A CoCoRaHS observer measured 6.3 inches of new snow to the west of Cora.
A combination of snow and blowing snow brought the closure of Highway 28 over South Pass.
Snow and blowing snow brought near zero visibility that resulted in the closure of Highway 28 over South Pass. A maximum wind gust of 94 mph occurred at Red Canyon with a prolonged period of wind gusts past hurricane force.
High winds occurred around Casper in Natrona County. The highest wind gusts were 73 mph along Wyoming Boulevard south of Casper and 71 mph along Hat Six Road in Evansville.
A 74 mph wind gust was reported at the Fales Rock RAWS site.
High wind occurred in northern Johnson County, with a maximum wind gust of 66 mph at the Johnson County airport near Buffalo.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Wyoming in 2023Every state in 2023This day in weather historyWarnings in Wyoming, March 2023
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: 1089132, 1089136, 1089137, 1089133, 1089135, 1089140, 1089138, 1089139.