The combination of a strong cold front moving across Wyoming and very strong low level winds mixing to the surface brought a widespread high wind event to much of western and central Wyoming. The highest wind gusts reported was 92 mph along the Chief Joseph Highway.
Every event with a place to put it; 17 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.
The combination of a strong cold front moving across Wyoming and very strong low level winds mixing to the surface brought a widespread high wind event to much of western and central Wyoming. The highest wind gusts reported was 92 mph along the Chief Joseph Highway. The most noteworthy gust was at the Natrona County airport near Casper. The wind gust of 90 mph was the all time record. Wind gusts of hurricane force were also reported in Fremont, Teton and Fremont Counties. All counties reported wind gusts past 58 mph.
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 28, 1:32 PM MST, 7 hours 30 minutes earlier.
Area Forecast Discussion National Weather Service Riverton WY 232 PM MDT Sun Mar 28 2021 .SHORT TERM...This Afternoon through Monday night Mid and high cloud cover has lingered over the forecast area early this afternoon, with the thicker clouds lee enhanced on the east side of the Wind River and Absaroka mountains. This has slowed solar heating, but these clouds should wane during the remainder of the afternoon with plenty of sunshine still possible. Shortwave ridge will translate east tonight as an open wave trough approaches from the west. This will set the stage for a very windy overnight and Monday as a strong cold front blasts east through western and central Wyoming. West of the Continental Divide...Pressure gradient tightens tonight with increasing south-southwest wind across the far west valleys and mountains. Moisture will not increase until very late tonight with light snow likely not beginning until around 10Z/Monday. Right- entrance region of a 130kt jet streak in combination with low-level frontal forcing will produce about a four- to six-hour period of enhanced snowfall over the northwest. The valleys could see a quick inch of snow around sunrise with two to four inches common in the mountains. Impressive 50kt 700mb wind will allow for ridge top winds gusting around 60 mph as the cold front moves through. This could create a period of hazardous travel over Teton and Togwotee passes during the morning commute, and possibly in open areas of Jackson Hole. The snow and wind decrease gradually after 15Z/Monday. Attention then turns to increasing west-northwest wind in the Upper Green River Basin and Sweetwater/south Lincoln counties for the remainder of the day as the front progresses east. High wind warnings have been posted for the southern zones, while gusts around 50 mph are not out of the question in the lower elevations of Sublette County. The winds will gradually decrease late in the afternoon, but 20 to 35 mph persist into the evening. As for precipitation, things should be fairly dry across the south. Across the northwest, moist northwest flow aloft will allow for lingering orographically-driven light snow showers across the northwest through the afternoon and evening. 500mb cold pool will aid instability with 700-500mb lapse rates topping 8C/km during that time frame. East of the Continental Divide...Conditions will be dry and warm overnight as the southwest wind begins to ramp up. Favorable 50 to 60 knot winds develop at 700mb across central Wyoming after midnight as the pressure gradient tightens ahead of approaching cold front. Impressive 80kt winds across the Absaroka Range and 60kt in the Wind River Range at 700mb. Downsloping gusts around 75 mph still seem plausible in these mountains and high wind warnings continue. Prone areas along the Cody and Lander foothills could still see gusts around 60 mph as Monday sunrise approaches. The cold front should reach the far north around sunrise, a Dubois to Buffalo line by 9AM, and through the entire forecast area around noon Monday. Strong northwest wind will follow in the wake of the cold front. This will slow speeds in those locations favored by southwest wind, while significantly boosting wind speeds in northwest-favored locales. These favored locations would include northern Johnson County, the northern Bighorn Basin, and the Wind River Basin. Gusts 60 to 65 mph seem a good bet as three-hour pressure rises top-out around 9mb. Peak speeds to occur during the late morning and early afternoon before beginning a very gradual decline into the early evening. Have upgraded the high wind watches to warnings and the timing remains good. The lower atmosphere will dry quickly behind the front with dew points falling into the single digits. As a result, relative humidity readings will be in the teens across the Bighorn and Wind River basins during the afternoon. Wind speeds continue to decrease late in the evening and overnight. The best chance for precipitation Monday will likely come along the I-25 and I-90 corridors, but am less than enthusiastic given the drying lower atmosphere. Have backed off from blended solutions. .LONG TERM...Tuesday through Sunday The start of the period has a longwave trough extending from the area of northern Minnesota through eastern Wyoming and into the southwest and a ridge axis extending over the EPAC. This puts Wyoming in a strong northwesterly flow which will keep cold air over the region. High temperatures Tuesday look to be the coldest of the period with highs mainly in the 30s and 40s. Some places in the higher elevations of the west and KP60 would probably not get out of the 20s. There may be some lingering snow showers over the northwestern mountains as well, but any amounts should be light with a very dry airmass. Any snow in those area looks to be completely over by 06Z Wednesday, if not before. After a cold morning Wednesday, with many places dropping into the single digits and teens, a quick rebound in temperatures is in store along with a period of dry and quiet weather. From Wednesday into Friday, expect about 10 degrees warmer each day and by the end of the week, temperatures in the 70s can be expected for areas east of the Divide and into the 60s west of the Divide. The higher mountain areas should approach 50. A leeside trough is shown on WPC guidance for Thursday and Friday so there may be some windy conditions for those days, especially in the east. By the end of the period, next Sunday, some precipitation may come back into the west ahead of the next system projected to move into the Pacific Northwest. The latest model run shows H7 temperatures now all above 0 degrees for Sunday so any accumulating snows do not look to be an issue at this point , but confidence is low due to it being out a full week. && .AVIATION...For the 18Z Issuance through 12Z Monday Issued at 1122 AM MDT Sun Mar 28 2021 A cold frontal system is projected to start impacting the area during the day tomorrow. KBPI/KPNA/KJAC and KCOD can expect VCSH starting between 12Z-15Z and remaining through the rest of the period, but VFR conditions look to prevail at these sites. Winds look to be the bigger factor with gusts between 40-45 knots for almost all terminals starting after 05Z and continuing for the rest of the period. && .FIRE WEATHER... A strong cold front will sweep east across Wyoming Monday. Ahead of this cold front, strong southwest wind will occur across central Wyoming with gusts 55 to 65 mph possible. The wind direction will gradually switch to the northwest Monday morning as the cold front pushes rapidly east between 6AM and noon. The result will be strong wind, falling relative humidity, and decreasing temperatures from late morning through sunset Monday. High wind warnings are in effect for many locations of the forecast area and elevated fire weather conditions are expected despite the falling temperatures. Basin portions of the Cody dispatch area will likely see relative humidity readings in the teens Monday afternoon. As for precipitation, there will be a four- to six-hour period of enhanced snowfall in the northwest mountains around sunrise as the cold front blasts east. The best chance for snow accumulation will be in the Teton Range and along the Continental Divide. Colder temperatures and moisture moving in from the northwest will allow for lingering snow showers Monday afternoon and evening. These will be most common over the northwest and northern mountains. Northwest flow aloft will keep temperatures well below normal Tuesday and light snow showers will linger over the northwest mountains. Seasonal temperatures return Wednesday with continued warming through the remainder of the week. && .RIW WATCHES/WARNINGS/ADVISORIES... High Wind Warning from 6 AM to 6 PM MDT Monday for WYZ004- 027>030. High Wind Warning from midnight tonight to 6 PM MDT Monday for WYZ002-003-015-018>020. High Wind Warning from 9 AM to 6 PM MDT Monday for WYZ010-011- 016-017. && SHORT TERM...CNJ LONG TERM...Clayton AVIATION...Clayton FIRE WEATHER...CNJ
Hazardous Weather Outlook National Weather Service Riverton WY 1220 PM MDT Sun Mar 28 2021 WYZ001>020-022>030-291300- 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- 1220 PM MDT Sun Mar 28 2021 ...Strong Wind Late Tonight and Monday Across Much of the Area... This Hazardous Weather Outlook is for Western and Central Wyoming. .DAY ONE...Rest of Today and Tonight Southwest wind increasing late today, but especially overnight across central Wyoming ahead of an approaching cold front. Strong wind gusts to 65 mph likely. Please see the High Wind Warning statement for more details. .DAYS TWO THROUGH SEVEN...Monday through Saturday Monday...The cold front sweeps across the area with strong northwest wind to follow. Northern portions of the Bighorn Basin and Johnson County, along with the Wind River Basin, will see the strongest wind gusts. Please see the High Wind Warning statement for more details. Accumulating snow is likely in the northwest and northern mountains early Monday. The bulk of the snow will come in a quick burst lasting 3 to 6 hours. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions, including strong wind gusts, according to standard operating procedures.
The national radar mosaic for the moment the first event began.
17 high wind. Local standard time, as filed.
A maximum wind gust of 92 mph was reported along the Chief Joseph Highway.
A 59 mph wind gust was reported at Clark, Wyoming.
A maximum wind gust of 64 mph was reported at the Lander, Wyoming airport.
Several locations in the Wind River Mountains had wind gusts past 74 mph. The highest recorded gust was 91 mph at the Red Canyon sensor along Highway 28.
Very high winds occurred along the high elevations of the Tetons. At the Jackson Hole Ski Resort, a maximum wind gust of 85 mph was recorded.
A 74 mph wind gust was recorded at the Fales Rock RAWS site.
A 60 mph wind gust was reported at the Jackson Hole airport.
High winds were reported across much of northern Johnson County, including a maximum wind gust of 64 mph at the Johnson County airport near Buffalo, Wyoming.
There were widespread reports of high winds across Natrona County, with many locations reporting hurricane force wind gusts. The wind gust of 90 mph at the Natrona County airport was the all time record gust. A maximum wind gust of 81 mph was recorded along Hat Six Road in Evansville, Wyoming.
A 58 mph gust was recorded at Crowheart, Wyoming.
A maximum wind gust of 63 mph was reported in Green River along Interstate 80.
A 59 mph wind gusts was reported at the Sweetwater County airport east of Rock Springs, Wyoming.
High winds were reported in Big Horn County. The highest gust was 69 mph at the South Big Horn airport near Greybull, Wyoming.
Wind gusts past 58 mph were recorded through much of the area. The maximum gust was 74 mph at the Worland, Wyoming airport.
A maximum wind gust of 61 mph was reported in Thermopolis, Wyoming.
A 60 mph wind gust was recorded at the Riverton, Wyoming airport.
A 58 mph wind gust was recorded near Kaycee, Wyoming along Interstate 25.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Wyoming in 2021Every state in 2021This day in weather historyWarnings in Wyoming, March 2021
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: 950690, 950691, 950687, 950686, 950702, 950688, 950699, 950695, 950689, 950697, 950693, 950694, 950692, 950701, 950700, 950698, 950696.