Shortwaves traversing a broader longwave trough across much of the western CONUS brought a round of snow to the region. Most impacts came in/near mountains and across the plains generally west of I-15.
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 TFX wrote it up.
Shortwaves traversing a broader longwave trough across much of the western CONUS brought a round of snow to the region. Most impacts came in/near mountains and across the plains generally west of I-15. Isentropic ascent combined with northwesterly surface winds to result in heavy and blowing snow, especially along the Northern Rocky Mountain front, where short-term (Less than 3 hrs) of whiteout conditions were observed.
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 Feb 2, 9:23 PM MST, 1 hour 37 minutes earlier.
Area Forecast Discussion National Weather Service Great Falls MT 923 PM MST Fri Feb 2 2024 .SYNOPSIS... Precipitation increases across the mountains of southwest Montana tonight with snow affecting many passes by Saturday morning. Tomorrow, lower elevations receive rain, which ultimately, transitions to snow, as temperatures cool to a more normal range for this time of year. Snow, gradually, ends on Sunday. Unsettled weather is forecast for next week, as well. && .UPDATE... Pacific moisture continues to stream in from the south and rain/snow is already underway along the Continental Divide and Southwest Montana this evening. The change over from rain to snow occurred pretty quickly over the higher terrain between Butte and Helena and tonight's temperatures were lowered for these areas per the current trends. Pops were added/increased tonight and Saturday morning over Central/North- central MT as light showers were already developing in this area. - RCG && .AVIATION... 511 PM MST Fri Feb 2 2024 (03/00Z TAF Period) Shortwave energy and Pacific moisture will stream south to north tonight into Saturday, bringing light rain, snow, and patchy fog. widespread MVFR/IFR conditions and mountain obscuration will continue to move into the remainder of Southwest Montana and areas along the Continental Divide through 02/06Z before slowly expanding northeastward onto the plains Saturday. There are some low clouds and patchy fog west of KHVR this evening and probabilistic guidance does give 30 to 40% chance for visibility reductions down to a half mile in this area tonight into early Saturday; however, the increasing presence of mid- and higher level clouds reduces confidence, so I have left the lower visibilities out of the TAF at this time. Winds will be light for much of the period, but will shift to the north and increase with the passage of a Canadian cold front after 03/00Z. - RCG Refer to weather.gov/zlc for more detailed regional aviation weather and hazard information. && .PREV DISCUSSION... /ISSUED 511 PM MST Fri Feb 2 2024/ Tonight through Saturday morning…A highly amplified upper level pattern with meridional flow exists across the western and central US with a large scale Pacific trough and upper level jet moving into the SW US undercutting an upper ridge shifting east into the central US today. Flow aloft becomes even more convoluted tonight through Saturday as the initial Pacific upper level trough energy emerges in the southern US plains, pulling an unseasonably deep plume of moisture northwestward into the region along a stretched upper level trough axis. Precipitation along the stretched trough axis is lifting north into SW MT this afternoon with webcams at Monida and Lost Trail passes showing some wet snow with snow levels currently near 6500–7000 ft. Moisture increases along this boundary as it lifts slowly northeast with precipitation reaching western portions of north-central MT and all of SW MT by Sunday afternoon. Snow levels will gradually fall through Saturday morning to as low as around 4500 ft with a mix or change to snow likely as the precipitation reaches the Bozeman area around noon. In the mountains of SW MT and along the continental divide snow will increase tonight with cooling and road surface temperatures likely leading to some road impacts over mountain passes by Saturday morning. Saturday afternoon through Sunday…A mid level wave lifting north into the region Saturday brings deeper moisture and turns mid level winds more easterly by Saturday afternoon across central and north-central MT, supporting a period of moderate precipitation across western portions of north-central/central MT as the wave lifts north through the area Saturday afternoon and evening. A weaker wave and its associated moisture lift north through the area Sunday afternoon with precipitation ending for most areas Sunday night. Meanwhile, an initially light northerly surface flow and easterly mid-level flow into the Rockies will help further lower snow-levels Saturday afternoon across the north-central MT plains allowing rain to begin to transition to snow at lower elevations there Saturday afternoon and evening. QPF forecasts are impressive for early February with 50% or higher probability of amounts exceeding 0.50” across most mountain locations and western portions of central and north-central MT. Snow accumulation forecasts have increased for areas adjacent to the Rocky Mtn Front east to I-15 where HREF (high-resolution model ensemble) guidance supports potential for a period of moderate to heavy snow Saturday evening. In addition, these areas will see increased north winds developing as higher surface pressure and colder air surge south along the Rockies adding blowing and drifting snow hazards to the mix for these areas, especially Saturday night. Winter storm warnings were expanded to cover these areas adjacent to the Rocky Mtn Front including Cut Bank south through Choteau, Augusta and Bowman's corner. Winter weather advisories were also added for lower elevation areas across southwest MT and western portions of north-central MT. The highest uncertainty regarding snowfall amounts exists across western portions of north-central MT along I-15, where an earlier transition to snow could result in higher amounts. Hoenisch Monday through next Friday...With upper level trofing dominating much of this period, temperatures hover closer to seasonal normals, with periods of mountain and low elevation precipitation. - Fogleman && .PRELIMINARY POINT TEMPS/POPS... GTF 36 40 23 32 / 30 90 100 90 CTB 33 39 17 28 / 30 80 100 80 HLN 34 36 29 33 / 90 100 90 70 BZN 31 35 28 36 / 90 100 90 60 WYS 24 29 20 30 / 90 100 90 70 DLN 32 35 30 37 / 100 90 90 40 HVR 28 38 23 35 / 20 30 100 100 LWT 31 38 29 35 / 20 70 90 90 && .TFX WATCHES/WARNINGS/ADVISORIES... Winter Storm Warning until 5 PM MST Sunday for Big Belt, Bridger and Castle Mountains-East Glacier Park Region-Eastern Glacier, Western Toole, and Central Pondera-Elkhorn and Boulder Mountains- Gallatin and Madison County Mountains and Centennial Mountains- Little Belt and Highwood Mountains-Northern High Plains-Southern High Plains-Southern Rocky Mountain Front-Upper Blackfoot and MacDonald Pass. Winter Weather Advisory from noon Saturday to 5 PM MST Sunday for Cascade County below 5000ft-Eastern Pondera and Eastern Teton-Eastern Toole and Liberty-Gates of the Mountains. Winter Weather Advisory from 11 AM Saturday to 5 PM MST Sunday for Beaverhead and Western Madison below 6000ft-Canyon Ferry Area-Gallatin Valley-Helena Valley-Madison River Valley-Missouri Headwaters-Ruby Mountains and Southern Beaverhead Mountains. Winter Weather Advisory until 5 PM MST Sunday for Northwest Beaverhead County. && http://www.weather.gov/greatfalls
The national radar mosaic for the moment the first event began.
6 heavy snow, 1 winter weather, 1 winter storm. Local standard time, as filed.
SNOTEL equipment at Wood Creek estimated 10 inches of new snow over the duration of the event.
Snotel equipment at Nevada Ridge estimated 10 inches new snow over the duration of the event.
Snotel equipment at Rocker Peak estimated 9 inches storm total snow.
Snotel Equipment at Nevada Ridge estimated 10 inches new snow for the event.
Snotel equipment at Black Bear south of West Yellowstone estimated 10 inches new snow over the duration of the event.
Multiple snow reports were made from lower elevations of Cascade county. Most were around 4 to 5 inches, but a single report of 6.5 inches was made 7 SSE of Ulm.
Co-op observer in Cut Bank measured 7 inches new snow over the 24 hours ending 5 AM MST Feb 4th. Start and end time for the zone was base off ASOS observations a few miles away from this observation.
Browning Law Enforcement Services made a social media post that mentioned severe driving conditions (icy/snow covered roads, blowing snow, poor visibility in some areas, and zero visibility in spots along US-2 and US-89. They recommended, but held short of enforcing, staying home to ride out the storm.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Montana in 2024Every state in 2024This day in weather historyWarnings in Montana, February 2024
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: 1150835, 1150836, 1150837, 1153704, 1150838, 1153705, 1150831, 1150833.