Arctic air once again spilled over the Divide the morning of the 8th leading to a period of gusty winds, blowing snow, moderate to heavy snowfall, icy conditions and much colder temperatures.
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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.
Arctic air once again spilled over the Divide the morning of the 8th leading to a period of gusty winds, blowing snow, moderate to heavy snowfall, icy conditions and much colder temperatures.
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 Feb 8, 3:45 AM MST, 7 hours 15 minutes earlier.
Area Forecast Discussion
National Weather Service Missoula MT
345 AM MST Thu Feb 8 2018
...Snow, Blowing Snow, and Much Colder Later Today into Friday...
.DISCUSSION...Arctic air is poised along the Divide and will
gradually make its way westward through the day bringing a period
of snow, blowing snow, and much colder temperatures to much of
western Montana later this morning into Friday morning. The most
severe winter conditions are expected from Badrock Canyon eastward
to Marias Pass along US 2, where heavy snow will combine with
strong wind gusts up to 50 mph, resulting in blowing snow and
very low visibility. Travel will become very hazardous.
Travel conditions will also become problematic for the lower
elevations of western Montana including the Kootenai River Valley,
the Flathead Valley southward to the Missoula Valley, and
southeastward to Butte. Although only a few inches of snow are
anticipated in the valleys, most of it will come in a short burst
and be accompanied by gusty winds. With this in mind, expect a
period of difficult travel for most valleys focused this afternoon
across the Flathead Valley working southward to the Missoula
Valley eastward to Butte this evening into early Friday. A helpful
animation can be found on the NWS Missoula Youtube page for those
wanting more details on the possible timing of the arctic air.
This storm system will also present a frostbite concern due to low
windchills and may be a danger to newborn livestock, please take
adequate precautions.
For North-central Idaho and Lemhi County, the cold air will be
greatly modified and much less impactful compared to western
Montana. Passes along the ID/MT border will see several inches of
snow with minor travel impacts, while lower elevations will see
rain and perhaps some very light snowfall.
Winter weather impacts will gradually diminish on Friday afternoon
as snowfall decreases but roads will continue to be slippery in
many areas.
A brief dry period is expected for Saturday into Sunday, as drier
and much colder air settles over the region. Low temperatures in
the teens to single digits (mainly for valleys along the
Continental Divide) can be expected. In addition, some freezing
fog will be possible by Sunday morning. Fog/stratus formation will
be key in determining how cold it gets for Sunday morning.
The next weather system is still on track to arrive later in the
day Sunday into Monday. It should remain cold enough for most all
locations to see some snowfall with this system. Forecast models
continue to show a couple potential brushes of arctic air early to
mid next week, however the timing of these features still remains
very much uncertain.
&&
.AVIATION...A big change is on the way later today but first
valley rain and mountain snow showers will continue with
periodically obscured terrain this morning. Breezy conditions are
also expected at KBTM this morning and will persist into the
evening, possibly gusting over 20 knots during the afternoon.
Arctic air will spill over the Divide later today and gradually
work south and westward with time, leading to a period of snow,
gusty winds, blowing snow with the associated reduced visibility
and lowered ceilings. The arctic air is expected to reach KGPI
around 08/2100Z, then arrive at KMSO and KBTM during the late
evening hours, most likely between 09/0400Z and 09/0700Z. Further
south, vicinity showers are likely near KSMN, but with limited
impacts to the airfield.
&&
.MSO WATCHES/WARNINGS/ADVISORIES...
MT...Winter Weather Advisory from 5 PM this afternoon to 11 AM MST
Friday Butte/Blackfoot Region...Potomac/Seeley Lake Region.
Winter Weather Advisory from 11 AM this morning to 11 AM MST
Friday Flathead/Mission Valleys...Kootenai/Cabinet Region.
Winter Weather Advisory from 11 PM this evening to 11 AM MST
Friday West Glacier Region.
Winter Storm Warning until 11 PM MST this evening West Glacier
Region.
ID...None.
&&The national radar mosaic for the moment the first event began.
3 winter storm. Local standard time, as filed.
Severe driving conditions were observed on U.S. Highway 2 due to a combination of falling snow and blowing snow as winds gusted to 50 mph. Power outages were also noted around Bad Rock Canyon and Swan Lake due to falling trees.
Severe driving conditions occurred in the Flathead and Mission valleys the evening of the 8th through the morning of the 9th due to snow and blowing snow. A peak wind gust of 56 mph occurred at Glacier Park International Airport at 4:46 pm on the 8th during the evening commute with minor power outages also noted.
A band of heavy snow developed over Missoula and the northern Bitterroot Valley during the morning commute on the 9th. Numerous traffic accidents occurred on key travel corridors as snow turned to slush and then froze to the roadways. A total of 5.7 inches of snow was observed at the Missoula International Airport.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Montana in 2018Every state in 2018This day in weather historyWarnings in Montana, February 2018
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: 732641, 732642, 733100.