Freezing rain was observed across Lincoln and Flathead Counties during the morning hours of December 7th and 8th.
Every event with a place to put it; 4 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.
Freezing rain was observed across Lincoln and Flathead Counties during the morning hours of December 7th and 8th.
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 7, 3:38 AM MST, 1 hour 22 minutes earlier.
Area Forecast Discussion
National Weather Service Missoula MT
338 AM MST Tue Dec 7 2021
.DISCUSSION...Northwest flow aloft with a weak upper level jet
stream moving through the region will continue to produce very
light snowfall through at least this morning. Additional snow
accumulations will be light (generally an inch or less) but slick
conditions will continue through the morning commute. Temperatures
for most valley locations are expected to warm above freezing
today. The one exception is across valleys of northwest Montana,
where more stubborn inversions will be slower to dissipate.
The next weather system will approach tonight, focusing
precipitation initially through northwest Montana and the Idaho
panhandle (I90 corridor and northward). With stubborn valley
inversions likely still in place in these areas, a wintry mix of
precipitation is expected. Forecast models continue to indicate
the potential for light freezing rain, which could make for
particularly slick conditions during the Wednesday morning
commute.
Warmer air is expected to raise snow levels through the day on
Wednesday as high as 4500 feet ahead of an approaching cold front.
Forecast models continue to indicate a tightening pressure
gradient, and with the atmosphere destabilizing, breezy winds are
anticipated, especially in the higher terrain. The cold front will
surge through central Idaho and western Montana Wednesday evening,
quickly lowering snow levels back to valley floors. Mountain
passes will likely be snow covered through this time period, with
some valleys also receiving some snow again by Thursday morning.
Colder conditions will settle over the region for Thursday into
Friday, with lingering precipitation in the terrain. The next
weather system arrives Saturday into Sunday. This weather system
has a tap into subtropical moisture and will likely lead to some
significant snowfall for the mountains across northwest/west
central Montana and north central Idaho. Valleys will also receive
snowfall, though how much is still in question. This certainly
could shape up to produce a decent valley snowfall, especially
across northwest Montana.
&&
.AVIATION...Light snow will continue this morning through the
terrain of central Idaho, and much of west- central Montana,
including at KMSO. Locally lowered visibility and terrain
obscurations will be the main concerns with snowfall.
Precipitation should become more focused on the terrain by mid
day.The next shortwave is set to arrive tonight into Wednesday
with more widespread mixed precipitation once again. Locations
across northwest Montana (including KGPI) could see a period of
freezing rain around 08/0900z, continuing into mid morning
Wednesday.
&&
.MSO WATCHES/WARNINGS/ADVISORIES...
MT...Winter Weather Advisory until 9 AM MST this morning
Missoula/Bitterroot Valleys.
Winter Weather Advisory until 9 AM MST this morning Lower Clark
Fork Region.
Winter Weather Advisory until 9 AM MST this morning
Bitterroot/Sapphire Mountains.
Winter Weather Advisory until 9 AM MST this morning
Potomac/Seeley Lake Region.
Winter Weather Advisory until 9 AM MST this morning
Butte/Blackfoot Region.
ID...Winter Weather Advisory until 8 AM PST this morning Northern
Clearwater Mountains.
Winter Weather Advisory until 8 AM PST this morning Southern
Clearwater Mountains.
&&PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MISSOULA MT
123 AM MST TUE DEC 7 2021
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1155 PM SNOW 6 NW MISSOULA 46.92N 114.09W
12/06/2021 M2.2 INCH MISSOULA MT CO-OP OBSERVER
CO-OP OBSERVER STATION MSOM8 MISSOULA 6 NW
WFO.
&&The national radar mosaic for the moment the first event began.
4 winter weather. Local standard time, as filed.
Freezing rain impacted US Highway 93 from Stryker to Whitefish. The public reported slick conditions and slow travel times.
Freezing rain was reported in the Flathead Valley during the morning commute of December 7th. Impacts were observed at Glacier Park International Airport, as officials noted a ton of deicer was needed. A trained spotter reported a glaze of ice on windshields in Columbia Falls.
A light glaze of ice from freezing rain impacted travel in the Flathead Valley from Kalispell to Bigfork.
Freezing rain was reported in Libby during the morning commute of December 8th. Residents reported slick roads and sidewalks.
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: 996867, 997232, 997236, 997228.