A combination of a cold front, a potent jet, and strong winds being mixed to the surface brought high winds to much of northern and central Wyoming. The highest wind speeds were near the foothills of the Absaroka Range, where wind gusts as high as 120 mph occurred to the west of Clark.
Every event with a place to put it; 10 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 combination of a cold front, a potent jet, and strong winds being mixed to the surface brought high winds to much of northern and central Wyoming. The highest wind speeds were near the foothills of the Absaroka Range, where wind gusts as high as 120 mph occurred to the west of Clark. These intense gusts downed a power line, which was responsible for igniting a wildfire in the Line Creek drainage north of Clark. The wildfire spread quickly and destroyed several structures and caused one death. Wind gusts to around 90 mph were reported in northern Johnson County downing power lines that sparked several small grass fires. Wind gusts over 58 mph were also reported in Fremont and Hot Springs counties.
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 Nov 15, 3:48 PM MST, 3 hours 8 minutes earlier.
Area Forecast Discussion National Weather Service Riverton WY 348 PM MST Mon Nov 15 2021 .SHORT TERM...(This evening through Tuesday night) Issued at 215 PM MST Mon Nov 15 2021 An anomalously amplified ridge has allowed for unseasonably warm temperatures this afternoon, with readings running 15 to 20 degrees above average. After a very warm start to the week, an incoming trough and attendant cold front will be quick to knock temperatures down to slightly below normal for mid-week. Strong winds will deliver the colder air, and these begin tonight for Wyoming. Winds are the primary concern with this system, as moisture is lacking and the lower elevations are unlikely to see much, if any, precipitation. High Wind Watches were upgraded to Warnings for many parts of western and central Wyoming last night, and these largely remain in effect, save for slight changes in the timing. Notably, high-resolution models are now showing potential for downslope mountain wave activity over portions of Johnson, Hot Springs, and Fremont counties, mainly in locations nearest the high terrain: Wind gusts in excess of 55 mph are possible starting during the early morning hours Tuesday, so have added additional High Wind Warnings to cover this threat. Winds mix down more broadly during the daytime hours Tuesday, and west and northwest gusts in excess of 45 mph range are expected for many basins, especially those east of the Divide. Winds will be strong in the western valleys too, but are less likely to gust over 50 mph. The strongest winds decrease after peak afternoon mixing, with High Wind Warnings ending for most areas during the evening. Breezy conditions continue into the overnight hours due to cold advection. Precipitation-wise, most snow showers will be fed by the moisture in the southwest flow ahead of the cold front itself. This leads to relatively high snow levels between 7000 and 7500 ft during the overnight and early morning hours Tuesday. Several inches of snow are possible in the highest mountain ranges, but only trace accumulations look likely for places like Pinedale in the Upper Green River Basin or Moose in the Teton Valley. Mountain passes are probably the place most likely for travelers to see light accumulations, with Teton and Togwotee Passes each seeing potential for 2 to 3 inches. Very little if any precipitation will fall east of the Divide, besides in the peaks of the Bighorns. Most showers end by Tuesday afternoon. After recent warmth, Tuesday night into Wednesday morning will feel quite chilly with lows in the upper single digits and teens. Wind chills may also come into play, with continued cold air advection dropping apparent temperatures into the single digits above zero. .LONG TERM...(Wednesday through Monday) Issued at 215 PM MST Mon Nov 15 2021 North/northwest flow behind the departing trough will continue to promote CAA into the region as reflected in the high temperatures for Wednesday. However, through the day Wednesday, the pattern will phase into upper-level ridging. This will prompt the warming and drying of the area through Friday. Models remain in agreement with a subtle shortwave digging into the area late Friday into Saturday. This looks to bring increasing chances for rain/snow showers to the western mountains. Models suggest that the bulk of this precipitation will remain along and west of the Divide but can't rule out some upslope snow showers along the Bighorn Mountains. Northwest flow sets up again behind Friday/Saturday's system bringing back the colder air to end the period. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 348 PM MST Mon Nov 15 2021 East of the Divide...KCOD/KCPR/KLND/KRIW/KWRL Terminals VFR conditions will prevail through the TAF period. The main impacts will be wind as strong winds will be prevalent through the period. Sustained winds of 20 to 30 knots will be possible at KCOD and KCPR with gusts to 40 knots. Sustained winds of 15 to 25 knots and gusts to 30 knots at KRIW and KLND through the period. KLND does have LLWS after 8Z/Tuesday through 17Z/Tuesday. Winds shift to the northwest before the end of the TAF period as a cold front passes through the area. Winds look to taper off toward the end of the period behind the departing cold front. Mountaintop obscuration will be likely through the period as CIGS remain relatively low. West of the Divide...KBPI/KJAC/KPNA/KRKS Terminals VFR conditions will prevail through the TAF period. The main impacts will be wind as strong winds will be prevalent through the period. Sustained winds of 20 to 30 knots will be possible at KRKS and KJAC with gusts to 35 knots. Sustained winds of 15 to 25 knots and gusts to 30 knots at KBPI and KPNA through the period. Winds shift to the northwest before the end of the TAF period as a cold front passes through the area. Terminals KJAC, KBPI and KPNA could experience VCSH after 9Z/Tuesday. Showers may create brief MVFR/IFR conditions. Winds look to taper off toward the end of the period behind the departing cold front. Mountaintop obscuration will be likely through the period as CIGS remain relatively low. 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 215 PM MST Mon Nov 15 2021 Winds will become strong and gusty tonight ahead of a cold front moving through Tuesday. Winds Tuesday may gust 45 to 60 mph in the basins and valleys, with gusts in excess of 75 mph possible overnight into Tuesday along eastern mid-slopes of the Absaroka, Wind River, and Bighorn Mountains. Light snow is expected above 7000 to 7500 overnight, but accumulations will be very light for all but the highest peaks. Strong winds keep temperatures mild on Tuesday, but temperatures drop to below normal on Wednesday. && .RIW WATCHES/WARNINGS/ADVISORIES... High Wind Warning from 5 AM to 5 PM MST Tuesday for WYZ030. High Wind Warning from 11 PM this evening to 5 PM MST Tuesday for WYZ007-015-016-019. High Wind Warning from 2 AM to 2 PM MST Tuesday for WYZ004-005- 018. High Wind Warning from 2 AM to 11 PM MST Tuesday for WYZ010-011. High Wind Warning from 8 PM this evening to 5 PM MST Tuesday for WYZ002-003-009-020. && SHORT TERM...VandenBoogart LONG TERM...Vorst AVIATION...Vorst FIRE WEATHER...VandenBoogart
Hazardous Weather Outlook National Weather Service Riverton WY 256 PM MST Mon Nov 15 2021 WYZ001>020-022>030-162200- 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- 256 PM MST Mon Nov 15 2021 ...High Wind Warnings are posted for parts of Northern and Central Wyoming tonight through Tuesday... This Hazardous Weather Outlook is for Western and Central Wyoming. .DAY ONE...This Afternoon and Tonight. Windy areas will occur today with gusts 30 to 40 mph in the wind corridor of central Wyoming, the Dubois area, and in the Cody Foothills. Wind speeds will be increasing tonight over northwest and central Wyoming. .DAYS TWO THROUGH SEVEN...Tuesday through Sunday. Tuesday...Strong wind and wind gusts are likely across parts of Southern, Central, and Northern Wyoming. Please see high wind statements. Friday...Snow returns to the western mountains as another system approaches for the weekend. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report snowfall amounts and any strong wind speeds, or damage from high wind gusts.
The national radar mosaic for the moment the first event began.
9 high wind, 1 wildfire. Local standard time, as filed.
High wind blew for several hours along Wyoming Highway 296 over Chief Joseph Pass. A maximum wind gust of 88 mph was recorded shortly after 2200MST.
Gap flow coupled with a mountain wave developed around Clark and brought extremely strong wind gusts for several hours on the evening of Monday, November 15. A maximum wind gust of 120 mph was reported to the west of Clark at 2100MST. A wind gust of 75 mph was measured at the Clark firehouse around midnight November 16.
Very strong wind downed a power line into a tree igniting a wildfire around 2215MST Monday, November 15, in the Line Creek area north of Clark. The starting point appeared to be in the 800 block of County Road 1AB. The wildfire rapidly spread through the Line Creek drainage, mainly the north side of the creek, as well as the area around Gunpowder Road as westerly wind gusting between 60 and 80 mph drove the flames eastward. The blaze, which eventually burned at least 300 acres, destroyed three homes, seven outbuildings, and a bridge. The fire was also responsible for the death of a 61-year-old woman who succumbed to smoke inhalation on Tuesday, November 16. Firefighters responded from across northern Park County and southern Montana to get the fire under control. Evacuations occurred for Louis L'Amour Lane and Crossfire Trail.
A peak wind gust of 65 mph was registered at a ranch near Mayoworth to the northwest of Kaycee near the foothills of the Bighorn Mountains.
A maximum wind gust of 76 mph was recorded at the School House RAWS.
The Grass Creek RAWS recorded a peak wind gust to 75 mph.
A maximum wind gust of 90 mph was reported by the wind sensor at Red Canyon. Wyoming Highway 28 over South Pass was closed for several hours as a result.
Downsloping wind produced a 67 mph gust at Hunt Field in Lander just prior to 0400MST. A mesonet station in the North Fork Popo Agie River drainage northwest of Lander recorded a peak gust of 58 mph.
Very strong winds occurred in northern Johnson County. A wind sensor along I-90 near the Johnson-Sheridan county line recorded a maximum wind gust of 92 mph. The ASOS at Johnson County Airport near Buffalo registered a peak gust of 82 mph. The high winds downed several power lines that ignited small grass fires throughout the area.
A 62 mph wind gust was reported at the Sharpnose RAWS. The ASOS at Central Wyoming Regional Airport in Riverton reported a peak gust to 58 mph.
As the offices recorded each death: direct deaths were caused by the weather itself, indirect ones by something it set in motion.
| Event | Date | Age | Sex | Where | Kind |
|---|---|---|---|---|---|
| Wildfire, Cody Foothills | 2021-11-16 | 61 | Female | Unknown | Direct |
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, November 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: 991832, 991833, 994212, 991838, 991839, 991840, 991834, 991841, 991837, 991842.