Two relatively mild and moist upper level waves dropped out of Canada, and brought snow and slick roads to western Montana. When the snow started, temperatures ranged from sub-zero single digits, to above zero single digits Fahrenheit. Road chemicals were not able to mitigate road surfaces at these temperatures, therefore resulting in very slick road conditions until temperatures were able to warm into the 20's to near freezing later on Dec. 10. There were multiple accidents reported, several included injuries, and one resulted in a fatality. The second upper level wave contained more moisture and the atmosphere was a little milder, allowing for larger snow crystal growth and higher snowfall amounts.

Winter Weather in POTOMAC / SEELEY LAKE REGION, MONTANA
From 09-DEC-13 04:47:00 to 11-DEC-13 04:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

The Seeley Lake RS COOP reported a three day storm total snowfall of 6.9 with 0.32 of liquid equivalent. The Kraft Creek SNOTEL, located 8 miles SSW of Condon measured 13 of snow by 7 am MST on Dec. 10.  There were multiple accidents and slide-offs reported during the storm. There was an injury reported with a crash that happened at 3:43 pm MST on Dec. 9, at the cross streets of MT-200 and Potomac Rd. Road conditions were snow-covered and icy at the time of the crash.

Winter Weather in FLATHEAD/MISSION VALLEYS, MONTANA
From 09-DEC-13 05:00:00 to 10-DEC-13 17:02:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Official NWS Observations

The Flathead and Mission Valleys saw the highest amount of snowfall in all of western Montana with this storm. Glacier Park International Airport reported a storm total snowfall of 10 with 0.41 liquid equivalent, while the ASOS reported mainly light snow intensities throughout the storm. A head-on automobile accident occurred near Moiese and the National Bison Range on MT Hwy-212 around 11 am MST on Dec 9. A 60 year old woman died as she lost control of her vehicle, and slid into the westbound lane striking an oncoming pickup truck injuring two people. Law enforcement reported that roads were icy at the time of the accident. A 5 vehicle accident occurred on US-93 near the Ninepipes Wildlife Refuge on Dec. 10. Law enforcement blamed the driver of a small U-Haul truck, for not stopping in time and rear-ending three other vehicles. Minor injuries were reported while road conditions were snow-covered and slick at the time of the accident. Several schools closed due to the weather on Dec. 10, including Salish Kootenai College located in Pablo, Polson, and Charlo schools. Two bus routes in the Ronan school district were canceled although schools stayed open. Other total snowfall amounts include: 13 Lake Blaine, 11.5 Polson Kerr DAM COOP, 11 4 SW Fort Connah, St. Ignatius, Creston and Columbia Falls, 10 Whitefish, and 8 at COOP station 13 S Bigfork.

Winter Weather in BITTERROOT / SAPPHIRE MOUNTAINS, MONTANA
From 09-DEC-13 04:00:00 to 10-DEC-13 16:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: SNOTEL

The Lolo Pass SNOTEL at 5,240 ft., reported a two day storm total snowfall of 12 with 0.50 of liquid equivalent. Temperatures started out at -1.5 deg. F and rose to 21 deg. by the end of the snowfall. The COOP located 14 miles northeast of Sula, reported 6.1 of snow with 0.23 of liquid equivalent.

Winter Weather in KOOTENAI/CABINET REGION, MONTANA
From 09-DEC-13 19:00:00 to 10-DEC-13 15:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

A person from the public in Olney tweeted that they received 11 of fluffy snow as of 11:59 am MST on Dec. 10.  At 6:40 pm MST, they commented that US-93 near mile-marker 145 was plowed but slick with ice and snow. Other storm snowfall amounts COOP stations include: 1.9 Yaak 9 NNE, 1.8 Libby 30 SSE, 2.5 Libby 1 NE, and 2.5 at the Eureka Ranger Station. The common 24 hour snow to liquid ratios, as observed by these COOP stations, ranged between 20 and 30 to one.

Winter Weather in WEST GLACIER REGION, MONTANA
From 09-DEC-13 23:00:00 to 11-DEC-13 15:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

The West Glacier Cooperative observer measured a storm total of 5.2 of snow with 0.22  liquid equivalent during this storm and temperatures ranged from the teens to lower 20's. The Hungry Horse Dam COOP reported 6.0 of total storm snowfall with 0.31 of liquid equivalent.

Winter Weather in LOWER CLARK FORK REGION, MONTANA
From 09-DEC-13 01:40:00 to 10-DEC-13 15:53:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

A cooperative observer located one mile west of Haugan, measured a storm total snowfall of 9 with 0.30 of liquid equivalent. The Superior COOP didn't report snow, but did report a liquid equivalent of 0.42, which could have equated to near a foot of snow, using a 30 to 1 snow to liquid ratio. The St. Regis schools closed on Dec. 10 due to the weather. Other snowfall reports include: 10 Thompson Falls, 7 Belknap 2 WNW, 6.4 in Alberton, and 6 Evaro.

Winter Weather in MISSOULA / BITTERROOT VALLEYS, MONTANA
From 09-DEC-13 04:00:00 to 10-DEC-13 12:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Official NWS Observations

The official Missoula International Airport storm total snowfall measured was 5.8 with 0.19 of liquid during this storm. The snow fell lightly on Dec. 9 and wreaked havoc on area roads causing multiple accidents due to slick conditions. At 11:37 am on Dec. 9, a 2 car crash on US-93 south of Florence left a woman and teenage boy with serious injuries. US-93 was shut down for several hours and authorities said that conditions were very slick at the time when the first car went out of control. At 1:54 pm MST on Dec. 9, a SUV rolled over in the flats, just north of Lolo on US-93, causing 2 people to be injured. Law enforcement indicated that the road was snow covered and icy at the time.