Winter Storm and Heavy Snow in Montana, February 3 to 4, 2017

Name: Winter Storm and Heavy Snow in Montana, February 3 to 4, 2017
Start: 2017-02-03T13:00
End: 2017-02-04T18:00
Location: Montana

February 3 to 4, 2017 · NWS MSO · 6 events in 6 counties and zones

Where it happened

Every event with a place to put it; 6 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.

Tornadoes
Tropical storms and surge
Floods
Wind
Hail
Winter weather
Heat and drought
Cold
Fire, smoke and dust
Marine and coastal
Other

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The toll

Deaths: 0
Injuries: 0
Property damage: $50,000
Crop damage: None recorded
Events: 6

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.

What happened

The episode as NWS MSO wrote it up.

Moist warm air moving over the Northern Rockies brought heavy snow and freezing rain to parts of western Montana. Valley locations saw periods of moderate to heavy snow as residual arctic air kept temperatures cool, especially in northwest Montana. One inch per hour snowfall rates were common, with some valleys receiving over a foot of new snow during a 24-hour period.

What forecasters said that day

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 3, 3:56 AM MST, 9 hours 4 minutes earlier.

Area forecast discussion, Feb 3, 3:56 AM MST, 9 hours 4 minutes before

Area Forecast Discussion
National Weather Service Missoula MT
356 AM MST Fri Feb 3 2017

...Mix of valley snow, rain and freezing rain this weekend will
create slick travel...

...Feet of snow expected in the mountains/mountain passes this
weekend into early next week...

.DISCUSSION...Very cold temperatures have developed across western
Montana and central Idaho this morning, with most locations in the
single digits for central Idaho and well below zero across western
Montana. An approaching weather system will begin to increase
cloud cover this morning, which will keep temperatures from
warming much in the valley locations.

The first wave of moisture in a series of very moist weather
systems will begin to spread into central Idaho and western
Montana this afternoon. Most locations will initially start out as
snow this afternoon. However, as warmer air works into the region,
pockets of freezing rain are expected to develop tonight into
Saturday morning, particularly through central Idaho and west
central Montana. Further north, across northwest Montana, enough
cold air is expected to linger to allow precipitation to fall as
all snow through Saturday. Needless to say, slick roads should be
expected area wide for travelers this weekend, with changeable
conditions over short distances. By Saturday afternoon, an
increase in winds aloft is expected to begin to cause some
downsloping effects, mainly for larger valleys such as the
Missoula/Bitterroot and Mission valleys. Breezy afternoon winds
are expected to allow the atmosphere to mix, which will bring many
valleys up into the mid to upper 30s. As precipitation type
transitions to rain across the lower valleys of Idaho on Saturday
into Sunday, the combination of melting snow and rain could cause
some drainage problems and ponding of water on roadways. (Please
see the HYDROLOGY portion of this discussion for more
information.)

Precipitation on Sunday will continue to be focused over the mountains
along the ID/MT border, as well as the mountains along the
Continental Divide (including and north of the Mission/Swan
ranges). These areas will continue to be pummeled by moisture
Sunday, Monday, and Tuesday as well. Additional one to two feet of
snow is possible during this timeframe down to mountain pass
levels.

For valleys, strong upper level winds will make it tough for much
moisture to reach valley floors due to downsloping effects Sunday
into Monday. The exception to this could be the northern Flathead
valley, the Tobacco valley, and west through Libby/Yaak/Troy.
These locations could overcome the strong winds and keep snow
falling throughout this time period.

Further enhancement of precipitation will then occur Monday
afternoon with decreasing downsloping effects, causing measurable
precip to finally make it down to the majority of valley floors.
Northwest Montana will likely remain as mostly snowfall Sunday
into Monday, however there could be a brief period of rain mixing
with snow Monday before the cold front finally crosses. Locations
who experienced rain or a rain/snow mix up to this point will
transition to all snow by Monday night.

Impacts during this time will continue to be intense, heavy,
dense mountain snowfall and inclement backcountry conditions, in
addition to a sloppy rain/snow mix in valleys. Additional snowmelt
due to elevated temperatures and snow levels will keep low-land
flooding one of our biggest concerns. Standing water on roads and
properties will be likely.
 &&

.AVIATION...The next Pacific weather system will start spreading
moisture over north central Idaho early this morning and into
western Montana by mid morning. Areas of light snow will gradually
spread into the region, mainly affecting KMSO and KGPI between
03/1500z and 03/2100z. Widespread obscurations of the terrain due
to snow and low ceilings should be anticipated. Late this
afternoon and evening, precipitation may begin to transition to a
mix of snow and freezing rain across central Idaho and west
central Montana. Airfield KMSO stands the best chance of seeing
some light freezing rain this evening and overnight tonight.
Meanwhile, moderate to heavy snow is expected to develop across
northwest Montana this evening and overnight, impacting KGPI with
low ceilings and visibility.

&&

.HYDROLOGY...A period of prolonged, intense precipitation will be
likely for north central Idaho and northwest Montana locations
Saturday through Monday. Rising snow levels and moderating valley
temperatures will be conducive to melting snow, and will be
coupled with prolonged, moderate to heavy rainfall. Initially, the
snowpack will absorb precipitation, but given the very long
timeframe for continued rain and melting snow, further impacts
will be possible, if not probable. Of most concern will be runoff
and standing water on roadways and properties, particularly those
with poor drainage.

&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...Winter Weather Advisory from 3 PM this afternoon to 5 PM MST
     Sunday Bitterroot/Sapphire Mountains.

     Winter Weather Advisory from 2 PM this afternoon to 5 PM MST
     Sunday Lower Clark Fork Region.

     Winter Weather Advisory from 5 PM this afternoon to 5 PM MST
     Sunday Flathead/Mission Valleys...Kootenai/Cabinet Region...
     West Glacier Region.

     Winter Weather Advisory from 6 PM this evening to 11 AM MST
     Saturday Potomac/Seeley Lake Region.

     Winter Weather Advisory from 4 PM this afternoon to 11 AM MST
     Saturday Missoula/Bitterroot Valleys.

ID...Winter Weather Advisory from 2 PM this afternoon to 4 PM PST
     Sunday Northern Clearwater Mountains...Southern Clearwater
     Mountains.

     Winter Weather Advisory from 2 PM this afternoon to 11 AM MST
     Saturday Eastern Lemhi County...Western Lemhi County.

     Winter Weather Advisory from 11 AM this morning to 10 AM PST
     Saturday Orofino/Grangeville Region.

&&

The radar

The national radar mosaic for the moment the first event began.

Open the radar archive at this moment

Event by event

3 winter storm, 3 heavy snow. Local standard time, as filed.

Winter Storm, West Glacier Region

When: February 3, 1:00 PM MST to February 4, 6:00 AM MST
Where: West Glacier Region forecast zone
Reported by: Department of Highways
Coordinates: 47.971, -114.069 (the zone’s center; the record gives no point)

The Montana Department of Transportation reported Severe Driving Conditions with blowing and drifting throughout the afternoon and evening of Feb. 3, lasting through the early morning of Feb. 4. They use this label sparingly, only when road conditions are treacherous. Road conditions improved by 7 am MST on Feb. 4. Glacier National Park officials estimated 8 inches of snow in West Glacier, MT between noon and 8 pm on Feb. 3rd, which translates to 1 inch or greater per hour snowfall rates.

Heavy Snow, Kootenai/Cabinet Region

When: February 3, 1:00 PM MST to February 4, 4:00 PM MST
Where: Kootenai/Cabinet Region forecast zone
Reported by: Emergency Manager
Coordinates: 48.171, -114.863 (the zone’s center; the record gives no point)

A local emergency manager estimated 8 inches of snow in Libby, MT in 24 hours with this event. A public report agreed with this estimate, also stating 8 inches of snow had fallen during the same time-frame, with 15 inches snow depth on ground. Plow drivers stated they had a hard time keeping up with the snow rates. On February 8th, the governor of Montana declared a State of Emergency to help in providing resources for snow removal. The Eureka, MT AWOS sensor, located at the airport, reported multiple hours of heavy snow, with 0.25 mi or 0.50 mi visibility for much of the event.

Heavy Snow, Flathead/Mission Valleys

When: February 3, 1:30 PM MST to February 4, 10:00 AM MST
Where: Flathead/Mission Valleys forecast zone
Reported by: Trained Spotter
Coordinates: 47.872, -114.424 (the zone’s center; the record gives no point)

A trained spotter in Kalispell reported 14 inches of snow during this 21 hour time-frame. Public reports came in reporting the worst driving conditions between Creston and Columbia Falls they have experienced in 30 years. Plow drivers also reported 12 to 14 inches of new snow in Columbia Falls, MT.

Winter Storm, Lower Clark Fork Region

When: February 3, 3:30 PM MST to February 4, 6:00 PM MST
Where: Lower Clark Fork Region forecast zone
Property damage: $50,000
Reported by: Department of Highways
Coordinates: 47.286, -114.685 (the zone’s center; the record gives no point)

Severe driving conditions were issued at 3:22 pm on Feb. 3 for a 33 mile stretch of I-90 leading up to Lookout Pass. Webcam images showed heavy snow throughout this time period. The Montana Department of Transportation reported at least two snow slides, one of which was at milepost 7, blocking individual lanes during the event. Highway patrol reported semi trucks stuck blocking lanes throughout the event, as well as semi truck accidents.

Heavy Snow, Bitterroot / Sapphire Mountains

When: February 3, 5:00 PM MST to February 4, 1:00 PM MST
Where: Bitterroot / Sapphire Mountains forecast zone
Reported by: Park/Forest Service
Coordinates: 46.508, -113.828 (the zone’s center; the record gives no point)

The public reported 15 inches of snow in 24 hours at Lolo Pass. Automated SNOTEL sensors suggested intense snowfall throughout the high terrain.

Winter Storm, Missoula / Bitterroot Valleys

When: February 4, 2:00 AM MST to 8:00 AM MST
Where: Missoula / Bitterroot Valleys forecast zone
Reported by: Department of Highways
Coordinates: 46.560, -114.023 (the zone’s center; the record gives no point)

Severe driving conditions were declared by the Montana Department of Transportation during the early morning hours of Feb. 4, due to snow-covered roads with blowing and drifting occurring. Freezing rain was also reported from Conner to Stevensville during the late evening of the 3rd.

What these are

Winter Storm: A storm that brought snow, sleet or freezing rain at warning levels, usually over several hours or days.
Heavy Snow: Snowfall reaching the local warning threshold without the other hazards of a winter storm.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

Every storm in Montana in 2017 Every state in 2017 This day in weather history Warnings in Montana, February 2017

Sources

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: 681639, 682434, 682443, 681662, 682450, 681670.