Extreme Cold and Winter Weather in Idaho, December 2 to 9, 2013

Name: Extreme Cold and Winter Weather in Idaho, December 2 to 9, 2013
Start: 2013-12-02T11:46
End: 2013-12-09T09:00
Location: Idaho

December 2 to 9, 2013 · NWS MSO · 4 events in 4 counties and zones

An arctic cold front pushes west and south over the Clearwater Mountains towards the lower elevations of the Camas Prairie. It brought several inches of snowfall to the region, caused temperatures to plummet to below normal readings, and caused road surfaces to be slick at times.

Where it happened

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.

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: 4

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.

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 2, 2:59 AM PST, 8 hours 47 minutes earlier.

Area forecast discussion, Dec 2, 2:59 AM PST, 8 hours 47 minutes before

Area Forecast Discussion
National Weather Service Missoula MT
359 AM MST Mon Dec 2 2013

.DISCUSSION...Most of the valleys overnight have remained warm
enough to keep precipitation as rainfall, however the mountains
are still racking up some impressive snow accumulations. Since the
cold air is taking some additional time to infiltrate western
Montana this morning, we are expecting rain to change over to snow
by mid to late morning, or this afternoon at the latest. Once this
occurs, it will be nothing but snowfall from here on out. Bitterly
cold air will funnel behind the frontal passage, and then the
winds will shift out of the north and east. This opens the door to
even colder arctic air that will impact northwest Montana tonight,
and then spread the rest of the way across western Montana and
central Idaho overnight into Tuesday.

The biggest impact we are expecting during this time will be
wet roads flash freezing due to the sudden onset of such cold
air. With zero breaks in precipitation nor clouds to help roads
dry off, every surface that is wet today will be a sheet of ice
tomorrow. Please take this into consideration for any travel you
intend to do.

Snow showers will then taper off as the center of the low moves
east of the Divide, but that doesn't mean the show is over. Very
strong east winds (sustained up to 30 mph with gusts up to 50 mph)
will combine with intensely cold temperatures to produce dangerous
wind chill values Tuesday morning into Tuesday afternoon. The
lowest and most dangerous values are expected across Flathead,
Powell, Deer Lodge, Silver Bow, and extreme east Missoula county.
Little ones that need to stand at their bus stop Tuesday morning
should take measures to protect exposed skin to prevent against
frostbite. But the danger of frostbite doesn't end on Tuesday with
gusty winds and very cold, frigid temperatures continuing
overnight and into Wednesday morning.

Winds will gradually subside on Thursday as the arctic air mass
becomes established across the region and the surface pressure
gradient relaxes. However, this break in the wind will be short
lived as yet another push of arctic air, perhaps even colder than
the first, will move into the Northern Rockies on Friday. But
since the difference in air masses will be subtle, extremely strong
winds are not likely at this time. Channeled canyons which lead as
passage ways over the Continental Divide (e.g. Badrock & Hellgate)
will see localized gusty winds and thus will once again be subject
to the dangers of extremely low wind chills Friday through Saturday
morning. Thus, those with plans to be outdoors this weekend should
plan accordingly for the danger of frostbite. Ambient air
temperatures will plunge even further into the freezer as stay
there through the weekend and perhaps even longer as some models
indicate yet a THIRD push of arctic air dropping out of Canada.
But confidence in this happening is very low at this time.

&&

.AVIATION...Aviation will see many factors that will impact travel
over the next 24 hours, and then some. Low visibility, low
ceilings, and gusty winds will be the main impacts, however all
around inclement flying conditions with icing issues at all
altitudes will be commonplace. Conditions will actually continue
to degrade further as strong winds aloft and rapidly changing
precipitation types cause further issues at all terminals.

&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...WINTER STORM WARNING until 1 AM MST Wednesday Butte/Blackfoot
     Region.

     WINTER STORM WARNING until 1 AM MST Wednesday
     Bitterroot/Sapphire Mountains...Lower Clark Fork Region.

     WINTER STORM WARNING until 1 AM MST Wednesday
     Missoula/Bitterroot Valleys.

     WINTER STORM WARNING until 1 AM MST Wednesday Flathead/Mission
     Valleys.

     WINTER STORM WARNING until 1 AM MST Wednesday Potomac/Seeley
     Lake Region...West Glacier Region.

     WINTER STORM WARNING until 1 AM MST Wednesday Kootenai/Cabinet
     Region.

ID...WINTER STORM WARNING until 1 AM MST Wednesday Eastern Lemhi
     County...Western Lemhi County.

     WINTER STORM WARNING until Midnight PST Tuesday Night Northern
     Clearwater Mountains...Southern Clearwater Mountains.

     WINTER WEATHER ADVISORY until Noon PST today Lower Hells
     Canyon/Salmon River Region...Orofino/Grangeville Region.

     WIND ADVISORY until 7 AM PST this morning for the Camas
     Prairie...Grangeville and Highway 95 IN THE Lower Hells
     Canyon/Salmon River Region...Orofino/Grangeville Region.

&&

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Allegretto/Dickerson

In the hours before

Local storm report, Dec 2, 7:01 AM PST, 4 hours 45 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MISSOULA MT
801 AM MST MON DEC 2 2013

...TIME...  ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
...DATE...  ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0642 AM     SNOW             5 NW EAST PORTAL        47.45N 115.69W
12/02/2013  M12.0 INCH       MINERAL            MT   PUBLIC

            THE LOOKOUT PASS SKI RESORT REPORTED 12
            INCHES IN THE LAST 24 HOURS AND 15 INCHES IN
            THE LAST 48 HOURS. ELEVATION 4800 FT. SNOW
            DURATION 24 HOURS

&&

NWS MISSOULA MT
IRIS SYSTEM

Local storm report, Dec 2, 7:37 AM PST, 4 hours 9 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MISSOULA MT
837 AM MST MON DEC 2 2013

...TIME...  ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
...DATE...  ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0833 AM     SNOW             1 SE BLACKTAIL          48.27N 113.44W
12/02/2013  M6.0 INCH        FLATHEAD           MT   PUBLIC

            THEY RECEIVED 6 INCHES OVERNIGHT AND IT
            CONTINUES TO FALL WITH 1 MILE VISIBILITY.
            THEY ARE LOCATED ABOUT 8 MILES SOUTHWEST OF
            MARIAS PASS AT 4400 FT. CURRENT TEMPERATURE
            IS 30 DEG. F. SNOW DURATION 9 HOURS

&&

NWS MISSOULA MT
IRIS SYSTEM

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 weather, 1 extreme cold/wind chill. Local standard time, as filed.

Winter Weather, Lower Hells Canyon / Salmon River Region

When: December 2, 11:46 AM PST to December 3, 4:15 PM PST
Where: Lower Hells Canyon / Salmon River Region forecast zone
Reported by: Department of Highways
Coordinates: 45.844, -115.467 (the zone’s center; the record gives no point)

The Whitebird Hill ITD sensor at 4,222 ft. on US-95, reported light snow that brought slick conditions during this period. It reported a very low grip level during this period which equates to very slick conditions.

Winter Weather, Orofino / Grangeville Region

When: December 3, 2:00 AM PST to 2:00 PM PST
Where: Orofino / Grangeville Region forecast zone
Reported by: Trained Spotter
Coordinates: 46.259, -115.562 (the zone’s center; the record gives no point)

A trained weather spotter, located 3 miles northeast of Orofino, measured 3.5 of snow that fell with the arctic cold front passage around 2 am PST. They reported that the roads were icy especially in shaded spots during the day on Dec 3.

Winter Weather, Southern Clearwater Mountains

When: December 3, 8:20 AM PST to 8:35 PM PST
Where: Southern Clearwater Mountains forecast zone
Reported by: Department of Highways
Coordinates: 45.844, -115.467 (the zone’s center; the record gives no point)

The ITD sensor at Elk City reported 3.2 of snow during the day on December 3.

Extreme Cold/Wind Chill, Eastern Lemhi County

When: December 6, 5:16 PM MST to December 9, 9:00 AM MST
Where: Eastern Lemhi County forecast zone
Reported by: Department of Highways
Coordinates: 44.943, -113.933 (the zone’s center; the record gives no point)

The ITD sensor at Lost Trail Pass on US-93, recorded wind chill values between -20 and -26 F, with wind speeds ranging between 5 and 12 mph. The -26 F value occurred on Dec. 7 at 1:16 pm MST with a wind speed of 10 mph, and also on Dec. 8 at 5:46 am MST with a wind speed of 5 to 7 mph. The Lost Trail Ski Area closed down due to the cold on Dec. 8. The Leadore COOP station observed a low temperature of -29 F on both Dec. 5 and Dec. 6. The value on Dec. 5 was the 2nd coldest minimum temperature for that day while back in 1972, the record was -38 F. The value on Dec. 6 was the coldest minimum for that day while 1972 was -15 F.

What these are

Winter Weather: Snow, sleet or freezing rain below warning levels that still caused disruption, damage or casualties.
Extreme Cold/Wind Chill: Temperatures or wind chills at or below the local warning criteria, or cold that caused deaths.

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

The same day elsewhere

Every storm in Idaho in 2013 Every state in 2013 This day in weather history Warnings in Idaho, December 2013

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: 495250, 495248, 495249, 495257.