A push of Arctic air came over the Continental Divide bringing windy conditions and low wind chill values.
Every event with a place to put it; 1 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 MSO wrote it up.
A push of Arctic air came over the Continental Divide bringing windy conditions and low wind chill values.
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 Missoula, MT wrote its last area forecast discussion before the first event at Dec 25, 3:28 PM MST, 1 hour 32 minutes earlier.
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</html>PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MISSOULA MT
1103 AM MST SAT DEC 25 2021
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1000 AM SNOW 6 N WHITEFISH 48.50N 114.34W
12/25/2021 M7.0 INCH FLATHEAD MT MESONET
MESONET STATION BIGMS 6.3 N WHITEFISH (GNP).
&&
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</html>The national radar mosaic for the moment the first event began.
1 extreme cold/wind chill. Local standard time, as filed.
Wind gusts of 15-25 miles per hour and well below zero air temperatures resulted in extended periods of wind chills of -30F to -50F. The coldest observed wind chill was -52F at the Snowslip sensor above US Highway 2.
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: 997622.