A strong pressure gradient, coupled with strong 60-80 knot winds at the mid levels, resulted in yet another round of gusty winds across the Plains of North-Central Montana, as well as a few areas in Southwest Montana, particularly in Madison County. Some snow also fell with this system, with 12 inches of snow reported at Teton Pass Ski Resort and 14 inches along the MT-ID border near West…
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 TFX wrote it up.
A strong pressure gradient, coupled with strong 60-80 knot winds at the mid levels, resulted in yet another round of gusty winds across the Plains of North-Central Montana, as well as a few areas in Southwest Montana, particularly in Madison County. Some snow also fell with this system, with 12 inches of snow reported at Teton Pass Ski Resort and 14 inches along the MT-ID border near West Yellowstone.
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 Great Falls, MT wrote its last area forecast discussion before the first event at Dec 10, 10:07 PM MST, 3 hours 8 minutes earlier.
Area Forecast Discussion National Weather Service Great Falls MT 1007 PM MST Fri Dec 10 2021 ...Aviation Section Updated... .SYNOPSIS... Strong southwesterly winds develop overnight and continue through Saturday, accompanied by moderating temperatures. Most areas will remain dry but accumulating snow is forecast along the eastern slopes of the Rocky Mountain Front. Areas of snow will expand across the Southwest Montana mountain ranges on Sunday and Monday. && .EVENING UPDATE... The Winter Storm Warning for the Northern Rocky Mountain Front was upgraded to a Blizzard Warning, given all the criteria required are anticipated tonight through Sunday morning leading to blowing snow and drifting now, creating whiteout conditions. The High Wind Watch for Madison County was canceled. All other known highlights remain unchanged. Otherwise, the forecast is handling the current situation well; therefore, not requiring any adjustments this update. - Pierce && .AVIATION... 1007 PM MST Fri Dec 10 2021 (11/06Z TAF period) VFR conditions prevail throughout the region this TAF period. Mountain obscuration is forecast, especially along the Rocky Mountain Front, as low- to mid-level cloudiness persist, and the increase of wintry precipitation through the period. Predominately southwesterly winds are expected to increase over the region tonight and into the morning, introducing mountain wave turbulence across the Rocky Mountain Front and immediate adjacent plains. Most terminals may also experience periods of low-level wind shear. Refer to weather.gov/zlc for more detailed regional aviation weather and hazard information. && .PREV DISCUSSION... /ISSUED 430 PM MST Fri Dec 10 2021/ Cool but mainly sunny conditions prevailed today as an upper level shortwave trough moved away to the east. Surface pressure analysis is showing pressure falls over southern Alberta. This trend will continue as upper level winds continue to strengthen. Mid-level winds reach 60 to 80kt overnight, enabling downslope surface winds to strengthen overnight. Surface winds are expected to peak Saturday morning and through the afternoon hours, with confidence for the strong wind remaining highest for the Rocky Mountain Front, the highway 200 corridor from Great Falls into Judith Basin county, and Chouteau county. Most of these areas have a 60 percent or greater chance for gusts reaching or exceeding 48 kts, with 80% or greater chance for wind gusts reaching or exceeding 56 kts in the Cut Bank, Browning, East Glacier, and Heart Butte areas. High wind Warnings continue for these areas. Strong winds are also expected across Southwest Montana on Saturday. However, probabilistic guidance indicates the strongest wind gusts exceeding 55mph are expected to remain over higher terrain, with 35 to 50 mph gusts through the valleys. The high wind watch that had been in effect for Madison County has been cancelled. Those heading out for backcountry recreation should be prepared for blowing snow and deepening wind loaded slabs on leeward slopes. Moisture is also increasing with the stronger westerly flow. Orographic snow will develop up the Continental Divide, with downwind transport out to the edge of the adjacent plains. Snow amounts of 6-12 inches may be possible along portions of Highway 89 in western Glacier County. Snow amounts will increase rapidly for those heading west on Highway 2 from East Glacier up to Marias Pass. The combination of snow and blowing snow in high winds will create very difficult conditions for travel in this area. A winter storm warning remains in effect overnight through Saturday. Snow may linger in this area through Sunday, while further expanding across mountain areas of Southwest Montana. PN Sunday night through next Friday...The pressure gradient relaxes some by Sunday across the region for lighter winds with temperatures cooling some, but remaining above seasonal averages through Monday under a southwest flow aloft ahead of a trough nearing the west coast. Medium range ensembles continue to bring the Pacific trough inland by the middle of next week, spreading better chances for accumulating snow and a period of colder temperatures. The placement of the low pressure system will have a big impact on how much snow falls and these details will be worked out over the next few days. -RCG && .PRELIMINARY POINT TEMPS/POPS... GTF 37 25 44 32 / 0 0 0 10 CTB 31 21 39 25 / 0 10 10 30 HLN 33 23 44 30 / 0 0 10 20 BZN 34 17 39 27 / 10 0 10 10 WYS 21 8 23 19 / 20 10 50 80 DLN 28 16 36 25 / 0 0 10 30 HVR 29 18 42 27 / 0 0 0 0 LWT 32 16 39 28 / 0 0 0 0 && .TFX WATCHES/WARNINGS/ADVISORIES... High Wind Warning from 11 PM this evening to 8 PM MST Saturday Cascade...Chouteau...Eastern Pondera...Eastern Teton...Judith Basin...Toole. High Wind Warning until 8 PM MST Saturday Eastern Glacier... Northern Rocky Mountain Front...Southern Rocky Mountain Front. Blizzard Warning from 2 AM Saturday to 11 AM MST Sunday Northern Rocky Mountain Front. && http://www.weather.gov/greatfalls
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
831 PM MST FRI DEC 10 2021
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0755 PM NON-TSTM WND GST 2 SE BROWNING 48.54N 112.98W
12/10/2021 M66 MPH GLACIER MT MESONET
MESONET STATION MTBWG BROWNING (MT DOT).
&&
BRUSDAPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
1012 PM MST FRI DEC 10 2021
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0930 PM NON-TSTM WND GST 14 W BYNUM 47.98N 112.61W
12/10/2021 M72 MPH TETON MT MESONET
MESONET STATION DELMT DELLWO (MCSCN).
&&16 high wind, 2 heavy snow, 1 winter weather. Local standard time, as filed.
Sensor 14 miles east of Townsend recorded a wind gust of 60 mph. This was the only report in the county through the event.
Widespread high winds. Peak wind gust of 88 mph recorded by a mesonet station along the Rocky Mountain Front (dellwo).
Wind gusts along the Rocky Mountain Front exceed 80 mph through the day, with isolated wind gusts over 90 mph at Deep Creek RAWS.
Estimated high sustained winds of 40 mph from about 5 am until about 4 pm. Peak wind gust estimated around 55 mph during that time.
Cut Bank ASOS reports high wind gusts through at least 10 am.
Winds across Choteau County gusted over 60 mph, starting at 6:15 and lasting through at least noon. Highest report occurred at noon at a mesonet station 10.2 miles south of Loma.
Wind gusts to 65 mph were measured across Judith Basin County through the day, with the highest wind gust of 65 mph recorded at Benchland at 8:45 pm.
Sporadic high wind gusts over 58 mph were recorded across Fergus County, with the peak wind gust of 68 mph recorded 7 ENE of Denton at 8:58 am.
Teton Ski resort in the mountains reported 12 inches of new snow.
Isolated wind gusts to 60 mph occurred in Southern Lewis and Clark County.
Multiple high wind gusts to 75 mph across the county. Highest wind gust (75 mph) was recorded 3 miles SE of Sunburst.
Mesonet station 6.4 miles SW of Havre reports wind gust of 66 mph.
Wind gusts between 58-61 mph were recorded across Gallatin County between 10:30 am and 2:45 pm on 12/11/21.
Norris hill recorded high wind gusts to 71 mph around for about an hour either side of noon.
Great Falls ASOS (kgtf) recorded a wind gust of 62 mph.
Automated SNOTEL equipment at Mount Lockhart estimated an event total of 16 inches of new snow. Equipment at Waldron estimated an event total of 11 inches of new snow. Equipment at Many Glacier estimated an event total of 7 inches of new snow. Equipment at Badger Pass estimated an event total of 9 inches of new snow.
Mesonet station 6 miles NW of Ledger reports high wind gusts to 71 mph.
Isolated wind gusts to 60 mph occurred in Liberty county.
Social media report of 14 inches of snow west of West Yellowstone. Appears to have been an isolated report.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Montana in 2021Every state in 2021This day in weather historyWarnings in Montana, December 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: 995112, 996677, 996625, 996654, 996624, 996593, 996627, 996606, 996681, 996628, 996660, 996626, 996622, 996631, 995113, 1076197, 996645, 996630, 996684.