Montana, 2014

Winter Weather in Montana, December 4 to 5, 2014

December 4 to 5, 2014 · NWS MSO · 2 events in 2 counties and zones

Mild and moist Pacific air moved over an arctic air mass located across western Montana and caused a myriad of precipitation types including freezing rain, sleet and snow. Below freezing temperatures continued throughout the event in the valleys which caused untreated surfaces to be very slick.

Where it happened

Every event with a place to put it; 2 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
1
Injuries
5
Property damage
None recorded
Crop damage
None recorded
Events
2

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.

Mild and moist Pacific air moved over an arctic air mass located across western Montana and caused a myriad of precipitation types including freezing rain, sleet and snow. Below freezing temperatures continued throughout the event in the valleys which caused untreated surfaces to be very slick. A fatality occurred in the Flathead Valley as a result of slick roads and driving too fast for conditions.

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 Dec 3, 5:25 PM MST, 8 hours 35 minutes earlier.

Area forecast discussion, Dec 3, 5:25 PM MST, 8 hours 35 minutes before
Area Forecast Discussion
National Weather Service Missoula MT
525 PM MST WED DEC 3 2014

...A MIX OF FREEZING RAIN AND SNOW WILL IMPACT PORTIONS OF NORTH
CENTRAL IDAHO AND WESTERN MONTANA THIS EVENING THROUGH THURSDAY...

.DISCUSSION...

A large swath of subtropical moisture will stream over the
Northern Rockies from the south beginning this evening, creating a
mix of snow, freezing rain, and rain over time. Many low and
mid-elevation valleys will experience periods of freezing rain or
drizzle mixed with snow by Thursday morning, then continuing
periodically throughout the day. We cannot stress enough that
roadway conditions will rapidly change from moment to moment and
place to place. Black ice (wherein a thin layer of ice develops
on pavement but deceptively appears as a dry surface) will be an
issue for area travelers. Overall, hazardous driving conditions
will arise from ice and snow covered roads. Valley temperature
inversions will persist, leading to increasing haze and air
particulates.

There is a slight chance of freezing rain redeveloping within the
valleys of northwest Montana Friday evening, although the more
likely scenario is snow or rain changing to snow. Snow
accumulations will be minor and mostly over high terrain.

A weak Pacific storm system is expected to bring another round of
mountain snow with a valley rain/snow mix Saturday. The main impact
will be snow over mountain passes, such as Lookout Pass and
Marias Pass, and associated hazardous driving conditions. Most of
the valley temperature inversions present across the Northern
Rockies will weaken or dissipate as this storm system passes. The
inversions will likely redevelop Sunday, however, as high pressure
returns.

The weather scenario of high pressure interrupted by periodic
Pacific storm systems every few days will continue across the
Northern Rockies past this weekend. Each storm system will bring a
complex mix of wintry precipitation; however, only modest
additions to mountain snowpack are expected at this time.

&&

.AVIATION...Clouds will quickly fill in by this evening as the
next wave of moisture approaches the region and moves through
tonight. Expect low cloud cover, decreased visibilities, and a
mix of rain, freezing rain, and snow tonight through Thursday as
the next weather system passes.

&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...WINTER WEATHER ADVISORY until 5 PM MST Thursday
     Bitterroot/Sapphire Mountains.

     WINTER WEATHER ADVISORY from 11 PM this evening to 5 PM MST
     Thursday Kootenai/Cabinet Region...Lower Clark Fork Region.

     WINTER WEATHER ADVISORY from 11 PM this evening to 5 PM MST
     Thursday Flathead/Mission Valleys...West Glacier Region.

     WINTER WEATHER ADVISORY from 11 PM this evening to 5 PM MST
     Thursday Potomac/Seeley Lake Region.

     WINTER WEATHER ADVISORY until 5 PM MST Thursday
     Missoula/Bitterroot Valleys.

ID...WINTER WEATHER ADVISORY until 8 AM MST Thursday Eastern
	 Lemhi County...Western Lemhi County.

     WINTER WEATHER ADVISORY until 7 AM PST Thursday 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

2 winter weather. Local standard time, as filed.

Winter Weather, Missoula / Bitterroot Valleys

When
December 4, 2:00 AM MST to December 5, 12:00 PM MST
Where
Missoula / Bitterroot Valleys forecast zone
Reported by
Official NWS Observations
Coordinates
46.560, -114.023 (the zone’s center; the record gives no point)

The Missoula International Airport received 1.7 of snow, sleet and freezing rain during the event. It initially started as snow with temperatures at 23 degrees and then started to mix with sleet by 6 am MST on Dec 4. It then changed to light freezing drizzle and rain by the evening hours causing black ice on side roads. The Bitterroot Valley saw an earlier change to freezing drizzle during the early morning hours. An observer in Florence reported 0.8 of snow before it changed to freezing drizzle. The slick conditions caused several vehicle slide-offs and accidents in the area.

Winter Weather, Flathead/Mission Valleys

When
December 4, 5:55 AM MST to December 5, 12:00 PM MST
Where
Flathead/Mission Valleys forecast zone
Deaths
1 direct, 0 indirect
Injuries
0 direct, 5 indirect
Reported by
Official NWS Observations
Coordinates
47.872, -114.424 (the zone’s center; the record gives no point)

The Glacier Park International Airport observers reported a storm snowfall total of 5.3 with 0.44 melted liquid and temperatures only rising from the mid-teens to the lower 20's during the event. The reports of freezing rain on top of snow were mainly found from the southern half of Flathead Lake and points south. Other reports include: Near 9 of new snow 5 miles north of Bigfork, 7 at Lake Blaine, 6 near Polebridge, 6 east of Polson towards the Mission Mountains, and 5 north of Whitefish. A 17 year old boy died as a result of a head-on crash between Bigfork and Somers on Montana Highway 82 on Dec. 4. The crash happened on a curve where road conditions were particularly slick and the Montana Highway Patrol commented that the boy was driving too fast for the conditions.

The people who died

As the offices recorded each death: direct deaths were caused by the weather itself, indirect ones by something it set in motion.

EventDateAgeSexWhereKind
Winter Weather, Flathead/Mission Valleys2014-12-0417MaleVehicle/Towed TrailerDirect

What these are

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

More

Every storm in Montana in 2014Every state in 2014This day in weather historyWarnings in Montana, December 2014

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: 544669, 544667.