A period of very warm temperatures ranging from 50 to 60 degrees occurred after an above normal snowfall winter across western Montana. This combined with moderate to heavy rainfall and high snow levels resulted in a quick melt of snowpack in various locations. Impacts felt included road closures due to avalanche danger, flooding of the Little Bitterroot River, rock slides across northwest Montana and lowland flooding across the Bitterroot Valley. President Obama declared a major disaster in the state of Montana which included Sanders, Lake and Ravalli Counties to help with the flood cleanup costs.

Flood in SANDERS, MONTANA
From 07-MAR-14 00:00:00 to 10-MAR-14 19:00:00 (MST-7)
Location: HOT SPGS ARPT
Flood cause: Heavy Rain / Snow Melt
Property damage: 4.00K
Crop damage: 0.00K
Reported by: Emergency Manager

The DES coordinator for Sanders County reported that the Little Bitterroot River flooded with 2 to 3 feet of water observed in places. The Little Bitterroot Road from Anderson's Corner to Sloan's Bridge was closed for 4 days. According to a river gauge located at one of the river's headwaters, Mill Creek, the discharge rate peaked at 238 cubic feet per second at 3:15 pm MST on March 6. In 31 years, this value surpassed the previous record of 53 cubic feet per second set back in 1986. A local rancher reported that this was the worst flooding he had ever seen. In terms of damage, the Little Bitterroot Road experienced minor damage with several culverts that needed to be replaced while homes were spared. Observations were sparse in the region, but a COOP observer located 2 miles northwest of Heron reported a 48 hour precipitation total of 1.99 between March 9-10. The combination of above normal snowfall that fell across western Montana in February, warm day and night-time temperatures and the rainfall contributed to substantial snow-melt in this event.

Heavy Rain in LINCOLN, MONTANA
From 04-MAR-14 00:00:00 to 06-MAR-14 13:00:00 (MST-7)
Location: LIBBY
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

Several days of moderate to heavy rainfall contributed to rock slides across northwest Montana. One in particular blocked a lane on Montana 37 north of the Libby Dam for a few hours.

Avalanche in WEST GLACIER REGION, MONTANA
From 06-MAR-14 04:00:00 to 07-MAR-14 17:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

Due to the large amount of precipitation between 1 and 2 inches in the mountains with high freezing levels, natural avalanche releases were reported between Essex and Marias Pass. A BNSF avalanche forecaster reported very large avalanche releases during the early morning hours on March 6. The MT DOT reported that US-2 between Essex and 7 miles west of Marias Pass was closed from 2 to 4:30 MST on March 6 due to avalanche mitigation. Both freight and passenger train service was shut down for an estimated 24 hour period between March 6-7.

Flood in LAKE, MONTANA
From 05-MAR-14 21:00:00 to 06-MAR-14 12:00:00 (MST-7)
Location: ROUND BUTTE
Flood cause: Heavy Rain / Snow Melt
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Broadcast Media

A driveway was completely washed out by a flood, presumably caused by snowmelt and very warm temperatures.

Flood in RAVALLI, MONTANA
From 06-MAR-14 00:00:00 to 07-MAR-14 10:00:00 (MST-7)
Location: FLORENCE
Flood cause: Heavy Rain / Snow Melt
Property damage: 16.00K
Crop damage: 0.00K
Reported by: Public

Above normal snowfall in February resulted in an unusually high snowpack across the Bitterroot Valley at the beginning of March. The Hamilton COOP reported a snow depth of 16 on March 2 which disappeared by March 9. Weather spotters in the Florence area reported well over a foot of snow at the beginning of March. This snowpack combined with 0.50 to 1 of mild rainfall and temperatures well into the 50's caused rapid snowmelt and subsequently overland flooding in the Bitterroot Valley. A person from the public in Florence off Hidden Valley Rd. reported a damaged fence, multiple homes with water damage and several windows broken. The MT DOT reported heavy water on the roadways S-203 2 miles east of Florence, near the junction with US-93. They also reported heavy amounts of water on S-203 10 miles north of the Stevensville Junction with S-269. The Ravalli County DES coordinator remarked that this was the worst flooding he had seen in 41 years in these areas.