A Pacific low pressure system brought accumulating snowfall to much of Southwest, Central, and North Central Montana. The passage of an associated cold front also brought gusty winds to much of the area, especially through the valleys of Southwest Montana, where heavier snow occurred.
Every event with a place to put it; 22 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 TFX wrote it up.
A Pacific low pressure system brought accumulating snowfall to much of Southwest, Central, and North Central Montana. The passage of an associated cold front also brought gusty winds to much of the area, especially through the valleys of Southwest Montana, where heavier snow occurred.
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 Mar 9, 4:45 PM MST, 3 hours 15 minutes earlier.
Area Forecast Discussion...corrected National Weather Service Great Falls MT 445 PM MST Thu Mar 9 2023 ...Aviation Section Updated... .SYNOPSIS... After a tranquil day today, wind and snow will return to the region overnight tonight and will linger through the day on Friday. Some of this snow may come in heavy bursts during the afternoon, resulting in rapid reductions in visibility. Tranquil conditions return over the weekend. && .DISCUSSION... Through Saturday... Currently in the calm between two weather systems, today has been a pleasant, if not chilly, day across North Central and Southwestern Montana. Temperatures have generally topped out in the 20s in the valleys of the Southwest, with teens across the plains under some filtered sunshine. However, there has been a gradual increase in the thickness of the clouds this afternoon as moisture begins to work in from the Southwest. As our next system approaches, winds will begin to increase across Southwestern Montana this evening and overnight tonight, with snow also developing over and near the Montana/Idaho border by later this evening. This snow will gradually spread northward overnight, reaching the North Central Plains by sunrise, where the steady snow will linger through most of the day on Friday. Further south, snow will be relatively brief during the overnight hours, and may actually appear to be over by the time many folks wake up in the lower elevations. However, this lack of snow in the morning will just be a bit of an illusion before the real show begins in the afternoon. This leads us to our big concern for tomorrow, bursts of very heavy snow potentially to snow squall criteria. The atmospheric setup is actually quite impressive for this, with Southwestern Montana being in the left exit region of the jet streak (which will promote lift), along with very strong PVA (Positive Vorticity Advection), which will also promote lift, and a surface cold front, which will serve as a focal point for the activity. Factor in the relatively warm and moist environment that this strong lift will be moving into, and you have yourself a fairly classic setup for intense bands of convective snow. The main focal point for this activity will be across Southwestern Montana, where the jet dynamics and PVA will be the strongest, but a few could work their way as far north as Great Falls. In addition to the intensity of the squalls, temperatures may rapidly drop behind the front, leading to a flash freeze. Current plan will be to continue to message the threat via social media, along with an SPS for areas not currently under a winter weather highlight early tomorrow morning. As a secondary concern, we will have a few areas of falling and blowing snow both along the MT/ID border and along the Hi-Line, particularly near and east of Havre. Once this system exits the region Friday night/Saturday morning, upper level ridging will build into the area and will linger through around the middle of next week. This ridge will result in relatively quiet weather for the region (save for a few periods of mountain snowfall) and gradually warming temperatures. Upper level troughing may try to work back into the area for midweek, but details remain uncertain at this time. Ludwig && .AVIATION... 445 PM MST Thu Mar 9 2023 (10/00Z TAF Period) We start this TAF period with VFR conditions. High to mid-level clouds continue to move into the region through the evening period as our next weather system moves in across Southwest Montana and along the Rocky Mountain Front tomorrow morning. Periods of blowing snow is expected this evening for KENS as winds will be gusting up to 30 knots. Beginning tomorrow late afternoon and evening, visibility will be reduced with IFR to LIFR conditions as bands of heavy snow move through the region. Low level wind shear across north-south orientated valleys in Southwest Montana such as KENS is expected tomorrow as winds have potential to gusting up to 55 knots. Mountain obstruction along the Continental Divide and across Southwest Montana Mountains begins tomorrow morning through the rest of the day tomorrow. Webb Refer to weather.gov/zlc for more detailed regional aviation weather and hazard information. && .PRELIMINARY POINT TEMPS/POPS... GTF 14 28 12 25 / 10 90 70 10 CTB 7 22 9 22 / 0 90 50 0 HLN 19 36 17 35 / 40 90 60 10 BZN 15 41 15 34 / 30 80 60 0 WYS 10 38 4 30 / 90 100 70 10 DLN 19 39 15 34 / 30 80 20 0 HVR 9 25 13 23 / 0 90 90 10 LWT 13 31 12 22 / 10 80 80 10 && .TFX WATCHES/WARNINGS/ADVISORIES... Winter Storm Warning from 2 AM Friday to 11 AM MST Saturday for East Glacier Park Region-Northern High Plains-Southern Rocky Mountain Front. Winter Weather Advisory from 5 AM Friday to 11 AM MST Saturday for Eastern Glacier, Western Toole, and Central Pondera-Eastern Toole and Liberty. Winter Storm Warning from 5 AM Friday to 2 PM MST Saturday for Bears Paw Mountains and Southern Blaine-Hill County-Northern Blaine County. Winter Weather Advisory from 5 AM to 5 PM MST Friday for Cascade County below 5000ft-Eastern Pondera and Eastern Teton-Fergus County below 4500ft-Judith Basin County and Judith Gap-Snowy and Judith Mountains-Southern High Plains-Western and Central Chouteau County. Winter Weather Advisory from 11 PM this evening to 11 AM MST Saturday for Big Belt, Bridger and Castle Mountains-Elkhorn and Boulder Mountains-Gates of the Mountains-Little Belt and Highwood Mountains-Meagher County Valleys-Northwest Beaverhead County-Upper Blackfoot and MacDonald Pass. Winter Storm Warning from midnight tonight to 5 AM MST Saturday for Gallatin and Madison County Mountains and Centennial Mountains-Ruby Mountains and Southern Beaverhead Mountains. High Wind Warning from midnight tonight to midnight MST Friday night for Beaverhead and Western Madison below 6000ft-Madison River Valley. && http://www.weather.gov/greatfalls
The national radar mosaic for the moment the first event began.
11 heavy snow, 6 high wind, 3 winter storm, 2 winter weather. Local standard time, as filed.
CO-OP observer station Simpson 6N Wildhorse (SIPM8) reported 6 inches of snowfall over a 24 hour period. Band of heavy snow occurred overnight along the International Border.
Strong winds resulted in poor visibility, blowing snow, and poor driving conditions. Wind gusts of 66 mph, 67 mph, and 73 mph were recorded at about 11 miles west of Emigrant, Virginia City and by the Yellowstone Mule RAWS, respectively.
Mesonet station Elk Peak Snotel reported 10 inches of snowfall. 9 inches fell by 5 AM on the 11th.
Two snotels reported an estimated 8 inches of storm total snow. Snotel sites Copper Bottom and Copper Camp estimated an event total amount of 8 inches. Most fell within a 12 hour period. Start time estimated by radar.
Trained spotter reported a storm total of 6 inches ending March 10 at 5:37 PM (Friday). The spotter received an additional three inches of snow overnight into the morning of the 11th ( 7:22 AM Saturday). Official NWS observation reported 6.3 inches snowfall between 5am Friday and 5am Saturday. NWS employee located 6 miles west of Sand Coulee reported an event total of 5.8 inches.
Rocky Boy Snotel reported 9 inches of snowfall for an event total.
Multiple trained spotters reported storm total snow of 6 inches or greater, including a reported 8.9 inches of snowfall 2 miles west of Helena.
Sheriff's office reported multiple accidents, extremely poor visibility, and strong gusty winds along I-15, which a portion of became closed for a period of time. Wind gusts in excess of 60 mph were recorded by the Harkness RAWS equipment.
CoCoRaHS observer in Cut Bank reported an event total snowfall of 5.5 inches.
Mesonet station GNFHY (10.7 W Emigrant) reported 65 mph wind gust.
COOP Observer neat Chester reported event total of 5.1 inches of snow, which met newly implemented heavy snow criteria for particular forecast zone.
MT DOT reported severe driving conditions from blowing snow and poor visibility along I-15. Conditions deteriorated rapidly. COOP observer at Conrad reported an event total snow amount of 7.0 inches along with significant blowing snow.
Wind gusts up to 64 mph were recorded across northern Blaine County, which resulted in significant blowing of snow, poor visibility, and poor driving conditions. COOP observer located about 11 miles north of Turner reported an event total snow amount of 11.5 inches.
Department of Transportation closed both lanes of S-232 northwest out of Havre to the International Border due to poor winter weather conditions. A trained spotter about 4 miles west of Havre reported an event total snow amount of 5.2 inches.
Mesonet station YCTIM (Yellowstone Club) reported 77 mph wind gust.
AWOS station KEKS (Ennis Big Sky) reported 62 mph wind gust.
Mesonet station MTM14 (BLM Argenta) reported 61 mph wind gust.
ASOS station KDLN (Dillon Airport) reported 64 mph wind gust.
Trained spotter reported a snow squall, which produced a quick accumulation of a half inch of snow. Spotter did not report any more details.
Snow Squall. The Bozeman Pass mesonet station (mtbzh) reported a peak wind gust of 53 mph. Webcam images showed poor visibility associated with the squall along Interstate 90.
Mesonet station MTNOR (Norris Hill) reported peak gust of 65 mph and sustained winds at 48 mph.
Spotter located about 17 miles WSW of Bynum reported an event total snow amount of 8.0 inches.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Montana in 2023Every state in 2023This day in weather historyWarnings in Montana, 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: 1084005, 1091405, 1083735, 1083999, 1084003, 1083989, 1083991, 1091363, 1089483, 1083727, 1092033, 1092035, 1092069, 1089489, 1083722, 1083732, 1083733, 1083730, 1087715, 1087716, 1083728, 1089492.