Winter Storm and Winter Weather in Montana, September 27 to 30, 2019

Name: Winter Storm and Winter Weather in Montana, September 27 to 30, 2019
Start: 2019-09-27T22:00
End: 2019-09-30T06:00
Location: Montana

September 27 to 30, 2019 · NWS MSO · 7 events in 7 counties and zones

An early season snowstorm brought heavy snow and gusty winds to parts of western Montana.

Where it happened

Every event with a place to put it; 7 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

Open the live radar over this ground

The toll

Deaths: 0
Injuries: 0
Property damage: None recorded
Crop damage: None recorded
Events: 7

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.

An early season snowstorm brought heavy snow and gusty winds to parts of western Montana.

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 Sep 27, 1:43 PM MST, 8 hours 17 minutes earlier.

Area forecast discussion, Sep 27, 1:43 PM MST, 8 hours 17 minutes before

Area Forecast Discussion
National Weather Service Missoula MT
243 PM MDT Fri Sep 27 2019

...MAJOR WINTER STORM IMPACTS BEGIN TONIGHT...

.DISCUSSION...The seasonally-historic winter storm is still on
track to begin tonight lasting into early next week. No major
changes were made to the forecast with most of the winter storm
watches upgraded to warnings, along with an expansion of the high
wind warning further westward in Northwest Montana. Here are the
primary anticipated impacts over the next few days:

-  Damaging winds possible across northwest Montana. Wind gusts
   of 40-50 mph are expected. Higher wind gusts to 55 mph are
   likely in the canyons along Highway 2 between Marias Pass and
   Kalispell, around Flathead Lake, and along Hwy 93 from just
   north of Whitefish to Eureka. Downed trees and power lines
   causing power outages is a big concern.

-  Extreme wave action on Flathead Lake could lead to boat and
   dock damage.

-  1 to 3 feet of snow across the mountains of the Continental
   Divide with 6 to 12 inches for the rest of the higher terrain.
   Travel will be very difficult to impossible in the backcountry
   while primary roads will experience periodic slick, snowpacked
   conditions. Snow combined with strong gusty winds will lead to
   very low visibility and blizzard-like conditions at times for
   Marias Pass and also MacDonald Pass.

-  1 to 3 inches of snow for lower valleys, 2 to 7 inches for
   higher valleys above 4,000 feet are expected in western
   Montana. Locations that experience the steadier snowfall could
   experience damage to tree branches and power lines.

-  Near record cold temperatures will follow early next week
   which will likely cause damage to sensitive vegetation and
   exposed irrigation systems.

Please check your local forecast for more detailed snow, wind, and
temperature impacts. The impacts and locations affected are too
numerous to list here. Also, please keep up-to-date on the latest
warnings and advisories.

&&

.AVIATION...Scattered showers, and even a lightning strike or two,
will be present across west central and southwest Montana through
28/0200Z before diminishing. The major winter storm we are
expecting to impact the region will begin tonight, with winds
strengthening at KGPI after 28/0400Z. Sustained N-NE winds up to
35 kts will be common, as will gusts to 50 kts. There is the
potential that winds of this magnitude could last for up to 48
hours once they begin. For KMSO, winds will become N-NE
around/after 28/0600Z and strengthen through the morning and
afternoon hours, with gusts to 40 kts possible. KBTM and KSMN
winds will increase much later (moreso towards 29/00Z). Snow will
begin to impact KGPI after 28/12Z. We expect further impacts from
snow, or a snow/rain mix, to occur at other terminals in the
coming days.

&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...Winter Storm Warning from 6 PM Saturday to 6 PM MDT Sunday
     Bitterroot/Sapphire Mountains...Butte/Blackfoot Region...
     Potomac/Seeley Lake Region.

     Wind Advisory from 9 AM Saturday to 3 AM MDT Sunday
     Missoula/Bitterroot Valleys.

     Winter Storm Watch from late Saturday night through Sunday
     morning Missoula/Bitterroot Valleys.

     Winter Storm Warning from noon Saturday to 6 PM MDT Sunday Lower
     Clark Fork Region.

     High Wind Warning from midnight tonight to 9 PM MDT Saturday
     Flathead/Mission Valleys.

     Winter Storm Warning from 6 PM this evening to 6 PM MDT Sunday
     West Glacier Region.

     High Wind Warning from midnight tonight to 9 PM MDT Saturday
     Kootenai/Cabinet Region.

     Winter Storm Watch from Saturday afternoon through Sunday
     afternoon Kootenai/Cabinet Region.

ID...Winter Storm Warning from 6 PM Saturday to 6 PM MDT Sunday ABOVE
     4500 FEET for the Eastern Lemhi County...Western Lemhi
     County.

     Winter Storm Warning from 11 AM Saturday to 5 PM PDT Sunday
     ABOVE 3000 FEET for the Northern Clearwater Mountains...
     Southern Clearwater Mountains.

&&

The radar

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

Open the radar archive at this moment

Event by event

6 winter storm, 1 winter weather. Local standard time, as filed.

Winter Storm, West Glacier Region

When: September 27, 10:00 PM MST to September 30, 5:00 AM MST
Where: West Glacier Region forecast zone
Reported by: Mesonet
Coordinates: 47.971, -114.069 (the zone’s center; the record gives no point)

Heavy snowfall was focused near the Continental Divide with 2 to 3 feet common. Social media videos from near Marias Pass indicated up to 4 feet of snow fell along with drifting snow as winds gusted to 40 mph. Further west in the Whitefish Range, general snowfall was 4 to 8 inches with wind gust to 50 mph at Big Mountain. Periods of hazardous travel were common on Highway 2, especially near Marias Pass due to the combination of snow, wind, and low visibility.

Winter Storm, Kootenai/Cabinet Region

When: September 28, 9:00 AM MST to September 29, 5:00 PM MST
Where: Kootenai/Cabinet Region forecast zone
Reported by: SNOTEL
Coordinates: 48.171, -114.863 (the zone’s center; the record gives no point)

Snow amounts of 2 to 4 inches fell in the valleys with 5 to 10 inches in the higher elevations, local amounts to 20 inches were observed at the Hawkins Lake SNOTEL. Also, wind gusts to 35 mph were reported in the higher terrain, locally over 50 mph at the western base of the Whitefish Range. Backcountry users experienced difficult travel.

Winter Storm, Bitterroot / Sapphire Mountains

When: September 28, 3:00 PM MST to September 29, 6:00 PM MST
Where: Bitterroot / Sapphire Mountains forecast zone
Reported by: Mesonet
Coordinates: 46.508, -113.828 (the zone’s center; the record gives no point)

General snow amounts of 4 to 8 inches fell, locally up to 12 inches. Also, wind gusts to 35 mph occurred. Difficult travel was experienced by backcountry users with periodic slippery, snow-covered, primary roads such as US-93 at Lost Trail Pass and US-12 at Lolo Pass.

Winter Storm, Lower Clark Fork Region

When: September 28, 10:00 PM MST to September 29, 5:00 PM MST
Where: Lower Clark Fork Region forecast zone
Reported by: Mesonet
Coordinates: 47.286, -114.685 (the zone’s center; the record gives no point)

Snow amounts of 1 to 3 inches fell in the valleys with 5 to 10 inches in the higher elevations. Also, wind gusts to 40 mph were reported in Thompson Falls and on some of the higher terrain. Difficult travel was experienced by backcountry users with periodic slippery, snow-covered, primary roads such as Interstate 90 at Lookout Pass.

Winter Storm, Butte / Blackfoot Region

When: September 29, 12:00 AM MST to September 30, 6:00 AM MST
Where: Butte / Blackfoot Region forecast zone
Reported by: Department of Highways
Coordinates: 46.306, -113.025 (the zone’s center; the record gives no point)

Periodic snow and gusty winds brought considerable travel impacts due to slick, snow-covered roadways and reduced visibility. Traffic accidents were common on Interstate 90, especially west of Butte on Sunday morning with chains required on Homestake Pass for a time. Snow accumulations of 4 to 10 inches were common which also limited backcountry travel.

Winter Weather, Missoula / Bitterroot Valleys

When: September 29, 3:00 AM MST to 5:00 PM MST
Where: Missoula / Bitterroot Valleys forecast zone
Reported by: Social Media
Coordinates: 46.560, -114.023 (the zone’s center; the record gives no point)

Light snowfall of 1 to 2 inches fell in the Missoula and Bitterroot valleys with up to 6 inches on the south side of Hamilton. While impacts were limited, this was an unusually early snowfall for valley locations.

Winter Storm, Potomac / Seeley Lake Region

When: September 29, 5:00 AM MST to 7:00 PM MST
Where: Potomac / Seeley Lake Region forecast zone
Reported by: SNOTEL
Coordinates: 46.986, -113.597 (the zone’s center; the record gives no point)

Snow accumulations ranged from 6 to 10 inches leading to difficult backcountry travel and occasional slick, snow-packed, primary roadways. Strong winds brought down numerous trees on local trails used by outfitters especially around Upper Holland Lake which significantly slowed packing operations.

What these are

Winter Storm: A storm that brought snow, sleet or freezing rain at warning levels, usually over several hours or days.
Winter Weather: Snow, sleet or freezing rain below warning levels that still caused disruption, damage or casualties.

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

The same day elsewhere

Every storm in Montana in 2019 Every state in 2019 This day in weather history Warnings in Montana, September 2019

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 2026-09-30. Each event’s entry at NCEI: 850636, 850624, 850650, 850645, 850703, 850704, 850702.