Very strong winds aloft combined with a favorable environment to allow severe wind gusts to reach the ground. A sudden snow shower which moved through the area, was especially helpful in bringing many wind gusts in excess of 60 mph to the surface for many locations.
Every event with a place to put it; 19 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 GGW wrote it up.
Very strong winds aloft combined with a favorable environment to allow severe wind gusts to reach the ground. A sudden snow shower which moved through the area, was especially helpful in bringing many wind gusts in excess of 60 mph to the surface for many locations.
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 Glasgow, MT wrote its last area forecast discussion before the first event at Jan 4, 1:30 PM MST, 2 hours 45 minutes earlier.
Area Forecast Discussion National Weather Service Glasgow MT 130 PM MST Sat Jan 4 2020 .DISCUSSION... Current headlines for High Winds will be left alone with this package as window of highest winds look to be from 3 pm-9 pm. 850mb winds reaching speeds that are uncommon (approaching 70 kts in the central zones around 03z) that are hard to ignore. Models have underplayed strong winds in this area and with the lack of a deep snowcover, winds tend to be stronger as higher temps lead to better mixing/lapse rates. Winds will gradually calm down later tonight. On Sunday, winds will be diminishing but still breezy as strong winds at mid-levels remain and flow at the surface direction is similar. Temperatures will be cooler with highs near 30 north to the low 40s south - still above normal. A weak front moves in early Monday that may bring high winds to SW Phillips county otherwise the next system moves in Monday Night. Some snow/rain look to threaten the SW zones and central Montana. An inch or less of accumulation can be expected. Went a bit higher on pops/qpf with this system that agrees with neighbors as well. Uncertainty arises beyond this as the pattern becomes more unsettled. The GFS is showing some snow and an arctic airmass holding the area in it's grips, while the ECMWF is lifting it northeast later this week. Model blend at this far out looks good. TFJ && .AVIATION... FLIGHT CONDITION: VFR WINDS: Becoming W 20-35 kts with gusts to 50 kts in the afternoon and evening. WIND SHEAR: May continue for OLF & SDY until about 2Z as stronger winds are brought to the surface. Look for strong, gusty, west winds this afternoon and evening. Mainly mid to high clouds today, high clouds overnight & tomorrow. Rux && .GLASGOW WATCHES/WARNINGS/ADVISORIES... High Wind Warning until 9 PM MST this evening for Central and Southeast Phillips...Central and Southern Valley...Garfield... McCone...Northern Phillips...Northern Valley...Petroleum... Prairie...Southwest Phillips. High Wind Warning until 3 AM MST Sunday for Daniels...Eastern Roosevelt...Richland...Sheridan...Western Roosevelt. High Wind Warning until 3 AM MST Sunday for Dawson...Wibaux. && weather.gov/glasgow
The national radar mosaic for the moment the first event began.
19 high wind. Local standard time, as filed.
At the BLM Zortman East mesonet site (MTM38), wind gusts of at least 58 mph were measured multiple times from 4:15 PM through 9:30 PM. The peak wind gust of 61 mph was recorded at 6:15 PM.
At the Malta South US-191 DOT site (MTMAL), sustained winds of at least 40 mph began at 5:15 PM and continued through 10:31 PM. The first severe wind gust (60 mph) was recorded at 5:20 PM. The peak wind gust of 64 mph was recorded at 6:30 PM.
At the Hillside MT-59 DOT site (MTHIL), the first verifying wind gust of 58 mph was measured at 6:38 PM, and the peak wind gust of 59 mph was measured at 6:56 PM.
At the South Sawmill Creek RAWS site (SSMM8), the peak wind gust of 64 mph was recorded at 7:08 PM, and a 62 mph wind gust was recorded at 9:08 PM.
At 3 SE Glasgow, the public reported shingles blown off a roof. Time and wind gust are estimated.
At the King Coulee RAWS site (KIGM8), the first verifying wind gust of 58 mph was recorded at 7:44 PM, and the peak wind gust of 63 mph was recorded at 8:44 PM.
The mesonet site just west of Glasgow (MTM72), recorded a peak wind gust of 62 mph at 7:45 PM and a 61 mph wind gust at 8:15 PM.
At the Glasgow airport ASOS site (KGGW), the first severe wind gust of 58 mph was recorded at 7:53 PM. Severe wind gusts continued for about the next hour, but there was a communications outage or some failure from the wind sensor, but NWS employees on shift were able to observe a maximum wind gust of 66 mph sometime between 8:18 PM and 8:50 PM. Times are estimated. By the time the wind sensor came back online at 9:53 PM, the severe winds had already dissipated.
In the town of Fort Peck, an off-duty NWS employee, via Facebook, reported a diagonal break through the trunk of a younger deciduous tree. Wind gusts of 65 mph estimated.
At the Cow Creek MT-13 DOT site (MTCOW), a single verifying peak wind gust of 58 mph was measured at 8:38 PM.
At the Badger Creek mesonet site (F2498), the peak wind gust of 61 mph was measured from 8:45 PM through 9:00 PM.
Trained spotter 2 W Van Norman, reported old cottonwood trees blown over onto grain bins. Time and wind gust estimated.
At the Circle Town County Airport mesonet site (KU46), the first verifying wind gust of 59 mph was recorded at 9:10 PM, and the peak wind gust of 62 mph was recorded at 9:25 PM.
At the Comertown Turn-Off MT-5 DOT site (MTCOM), sustained wind speeds of at least 40 mph were measured at least each hour for about two and one-half hours on the night of the 4th.
At the NDAWN station, 1 NW Sidney, a 62 mph wind gust was measured at 9:26 PM.
At the Lindsay Divide MT-200 DOT site (MTLND), the first verifying wind gust of 60 mph was measured at 9:33 PM, and peak wind gusts of 63 mph were measured from 9:38 PM through 9:44 PM.
At the Glendive airport ASOS site (KGDV), a peak wind gust of 58 mph was recorded at 9:56 PM.
At the Beaver Hill I-94 DOT site (MTBVR), a peak wind gust of 69 mph was measured at 10:08 PM.
At the BLM Glendive mesonet site (MTM28) at the southern edge of Dawson County, the first verifying wind gust of 61 mph was recorded at 10:45 PM, and the peak wind gust of 63 mph was recorded at 11:00 PM.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Montana in 2020Every state in 2020This day in weather historyWarnings in Montana, January 2020
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: 872929, 872939, 873314, 873053, 873300, 873068, 873316, 872933, 873071, 873076, 873353, 873301, 873121, 873340, 873136, 873289, 873292, 873298, 873356.