Surface low pressure gradually deepened in lee of terrain across Northern MT and Southern AB ahead of a shortwave approaching the region during the 18th. As mid level flow increased, strong winds developed, eventually spreading across most of the region heading into the 19th behind a cold front.
Every event with a place to put it; 15 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.
Surface low pressure gradually deepened in lee of terrain across Northern MT and Southern AB ahead of a shortwave approaching the region during the 18th. As mid level flow increased, strong winds developed, eventually spreading across most of the region heading into the 19th behind a cold front.
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 18, 4:54 PM MST, 4 hours 36 minutes earlier. Its key messages:
Area Forecast Discussion National Weather Service Great Falls MT 454 PM MST Thu Dec 18 2025 Aviation Section Updated. .KEY MESSAGES... - Winds increase again overnight into Friday. - Periods of moderate snowfall develop tonight through Friday over most mountain areas, heaviest along the Continental Divide. - Mainly dry conditions follow for the weekend. && .DISCUSSION... /Issued 228 PM MST Thu Dec 18 2025/ - Meteorological Overview: A stationary front resides across central Montana, with colder air entrenched over Hill, Blaine and portions of Fergus counties. Moisture arriving on a strong westerly jet stream will generate snow tonight into Friday over most mountain areas, heaviest along the Continental Divide. This disturbance will also create another round of strong winds late overnight into early Friday. The strongest wind gusts are expected along and adjacent to downslope areas of North-central Montana. This will be a more typical wind event producing limited impacts, not like the widespread wind storm we experienced Wednesday. Broad ridging follows into the weekend, resulting in a less windy and drier weekend ahead. - Forecast Confidence & Scenarios: There is a 80% or higher probability of gusts in excess of 55 mph where High Wind Warnings are in effect. The wind event on Wednesday may have left some infrastructure in a weakened state and stronger winds tonight to early Friday may hamper ongoing recovery efforts. && .AVIATION... 19/00Z TAF Period VFR conditions will prevail across all terminals during the duration of this TAF Period except for at the KEKS terminal. At the KEKS, KBZN, and KHLN terminals there is at least a 20 - 50% chance for snow, rain, and/or a rain/snow mix between now and 19/09Z. At the KGTF, KBZN, KHLN, and KEKS terminals between 19/13Z and 19/17Z there is at least a 25% chance for rain. This will bring MVFR- level visibility and ceilings temporarily to the KEKS terminal. Tonight there is a very low chance of light freezing rain occurring at the KHVR terminal. The biggest impact of this TAF Period will be another round of strong winds. Winds at the KEKS, KCTB, and KGTF terminals will gust in excess of 45 kts for several hours during this TAF Period with wind gusts in excess of 35kts expected at the rest of the terminals during this TAF Period. There will be widespread mountain wave turbulence and low-level wind shear during the duration of this TAF Period. During the duration of this TAF Period there will be mountain obscuration. -IG && .PRELIMINARY POINT TEMPS/POPS... GTF 37 49 28 40 / 30 30 0 0 CTB 29 40 17 36 / 30 10 10 10 HLN 33 47 24 38 / 70 80 10 10 BZN 32 49 18 37 / 50 40 10 0 WYS 21 37 7 25 / 90 60 10 10 DLN 33 49 18 34 / 80 40 10 0 HVR 25 42 5 23 / 30 10 0 0 LWT 31 47 20 36 / 20 20 10 0 && .TFX WATCHES/WARNINGS/ADVISORIES... Winter Weather Advisory until 6 PM MST Friday for East Glacier Park Region-Southern Rocky Mountain Front. High Wind Warning from 8 PM this evening to 6 PM MST Friday for East Glacier Park Region-Eastern Glacier, Western Toole, and Central Pondera-Northern High Plains-Southern High Plains- Southern Rocky Mountain Front. High Wind Warning from midnight tonight to 6 PM MST Friday for Cascade County below 5000ft-Eastern Pondera and Eastern Teton- Eastern Toole and Liberty-Judith Basin County and Judith Gap- Little Belt and Highwood Mountains. Winter Weather Advisory until midnight MST Friday night for Gallatin and Madison County Mountains and Centennial Mountains. High Wind Warning until 6 PM MST Friday for Madison River Valley. Winter Weather Advisory until 9 PM MST Friday for Northwest Beaverhead County. && http://www.weather.gov/greatfalls
Preliminary Local Storm Report
National Weather Service Great Falls MT
747 PM MST Thu Dec 18 2025
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0530 AM High Sust Winds 4 NNE Mcallister 45.50N 111.70W
12/17/2025 M44 MPH Madison MT Dept of Highways
MT DOT sensor Norris Hill (MTNOR) measured
sustained winds averaging 44 mph between 3
AM and 530 AM.
&&
AMPreliminary Local Storm Report
National Weather Service Great Falls MT
749 PM MST Thu Dec 18 2025
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0830 AM High Sust Winds 5 NNE Cameron 45.27N 111.65W
12/17/2025 M41 MPH Madison MT AWOS
AWOS station Ennis Airport KEKS measured
sustained winds averaging 41 mph between 650
AM and 830 AM.
&&
AMPreliminary Local Storm Report
National Weather Service Great Falls MT
756 PM MST Thu Dec 18 2025
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0145 PM High Sust Winds 1 NE Belgrade 45.79N 111.16W
12/17/2025 M40 MPH Gallatin MT ASOS
ASOS station KBZN Bozeman Airport measured
sustained winds averaged over an hour of 40
mph.
&&
AMPreliminary Local Storm Report
National Weather Service Great Falls MT
758 PM MST Thu Dec 18 2025
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0325 PM High Sust Winds 1 NE Belgrade 45.79N 111.16W
12/17/2025 M40 MPH Gallatin MT ASOS
ASOS station KBZN Bozeman Airport measured
sustained winds averaging 40 mph over the
hour prior to report time.
&&
AMPreliminary Local Storm Report
National Weather Service Great Falls MT
805 PM MST Thu Dec 18 2025
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0335 PM High Sust Winds 6 SE Jackson 45.32N 113.31W
12/17/2025 M41 MPH Beaverhead MT Dept of Highways
MT DOT sensor Big Hole Pass (MTBHP) measured
sustained winds averaging 41 mph between 931
AM and 335 PM.
&&
AMPreliminary Local Storm Report
National Weather Service Great Falls MT
822 PM MST Thu Dec 18 2025
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0820 AM High Sust Winds 2 SSW Virginia City 45.27N 111.96W
12/17/2025 M45 MPH Madison MT Mesonet
NW Energy sensor 011NW Cornucopia Rd
measured sustained winds averaging 45 mph
over an hour.
&&
AMThe national radar mosaic for the moment the first event began.
15 high wind. Local standard time, as filed.
AWOS station KEKS Ennis Airport measured a 58 mph gust. Additionally, mesonet station MTNOR Norris Hill (MT DOT) measured sustained winds averaged over an hour, of 41 mph.
A few sensors measured gusts of 58 mph or greater, including ASOS station KGTF Great Falls Airport, mesonet station MTM76 Cascade E MDA, Montana mesonet stations Belt NW and Eden NW, and AWOS station K1IM India. The peak gust was 63 mph and was observed at the Cascade E MDA sensor.
Mesonet station MTM02 10.2 S Loma measured a 61 mph gust.
Multiple sensors measured gusts of 58 mph or greater, including ASOS station KLWT Lewistown Airport, AWOS stations K1OM Oscar and KMVH N Bar Ranch, ns mesonet stations MTBOH Bohemian Corner (MT DOT) and MTBCH Beacon Hill (MT DOT). The peak gust observed was 70 mph at K1OM Oscar.
Multiple sensors measured gust of 58 mph or greater, including AWOS station K1CM Charlie, and mesonet stations MTGYS Geyser (MT DOT), MTEDD Eddies Corner (MT DOT), and MTM47 Benchland. The peal gust observed was 68 mph at K1CM.
Mesonet station MTMDP MacDonald Pass (MT DOT) measured a 59 and 60 mph gust.
ASOS station KCTB Cut Bank Airport measured a 61 mph gust.
A few sensors in this zone measured gusts of 58 mph or greater, including RAWS station TT838 Battle Ridge, and mesonet stations MTBZH Bozeman Pass (MT DOT) and MTBDC Bridger Canyon (MT DOT). The peak gust was 74 mph at Battle Ridge.
Three reports of gusts of 58 mph or greater were received, including ASOS station KBZN Bozeman Airport, mesonet station FW1650 Bozeman, and a trained spotter report from 3 NW Amsterdam. The peak observed gust was from the trained spotter (64 mph). Emergency management at MSU Bozeman reported two large trees fell down on campus.
Montana mesonet station Dog Gun Lake E measured an 81 mph gust.
Mesonet station MTM18 6.8 SE Melrose measured a 59 mph gust.
RAWS station FBLM8 Fort Belknap measured a 62 mph gust.
Wunderground sensor KMTAUGUS3 Upper Elk Creek measured a 64 mph gust. Given this zone does not have many sensors that are not sheltered, this 64 mph gust is treated as sufficient for verification purposes, even with the zone criteria being 75 mph.
Mesonet station MTMON Monarch Canyon (MT DOT) measured a 59 mph gust.
RAWS station HRKM8 measured a 61 mph gust.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Montana in 2025Every state in 2025This day in weather historyWarnings in Montana, December 2025
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: 1306468, 1306442, 1306445, 1306448, 1306450, 1306464, 1306459, 1306451, 1306452, 1306461, 1306470, 1306440, 1306467, 1306444, 1306439.