Flooding and Strong Wind in Montana, December 10 to 12, 2025

Multiple power poles and lines were knocked down near Jacob’s Island Dog Park, leaving parts of Missoula and the University of Montana district without power for approximately three hours. The outage delayed the first-ever UM vs. Salish Kootenai College basketball game and impacted traffic lights and businesses along East Broadway. Additionally, a large tree was reported down across US-93 in Darby at milepost 31 at 1616MST.

Power outages were reported from Clinton south to Rock Creek during the early evening hours. Winds were gusting 50 to 60 mph in the higher terrain above.

Heavy rain in the mountains caused flooding and significant erosion of forest service roads in western Mineral County. In the Superior Ranger District, the Deer Creek Bridge was compromised as the St. Regis River eroded the north bank, severely damaging the surrounding roadbed. Further west, reports from the Ward Creek drainage (National Forest Service Road 889) confirmed a complete washout, forcing the closure of a 7-mile stretch from Milepost 4.5 to 11.9. A hunter driving out of the mountains along Big Creek reported driving through feet of water at times and encountering falling trees that blocked the road. A plugged pipe at Milepost 1.5 up the East Fork of Big Creek caused the road to be completely covered with rock and debris.

At approximately 0400MST on December 11, a massive landslide occurred near Eagle View Lane, roughly 2 miles south-southwest of Bull Lake. The debris flow significantly damaged a residential garage, and the residents were unharmed. An Emergency Declaration was issued to address the lowland flooding and debris removal. Highway 56 near Bull Lake was forced to close between mileposts 16.7 and 17.2 after overwhelmed culverts allowed stream overflow to inundate the roadway. The emergency manager reported that over a dozen properties were isolated from Highway 56, either by a foot of water over access bridges or by an approximate 50-yard-wide flow of sediment-laden water separating residences from the main road. |A bridge on Montana Highway 471/Thompson Pass Road, near milepost 15, was washed out by Prospect Creek, resulting in a road closure. Prospect Creek also flooded the Prospect Creek campground at the Wild Coyote, located 7 miles up Prospect from Highway 200.

Notable infrastructure losses included the Farm-to-Market Road state bridge over Libby Creek, the Granite Creek county bridge, Ramsey Creek Bridge at milepost 8.9, Old Town/Libby Creek Bridge 8.1 miles up Libby Creek Road(NFS Road Number 231), West Fisher Road bridge over Lake Creek at about the 5.5 milepost, the Lower Granite Creek Bridge at milepost 2.5 on National Forest Service(NFS) Road 4791, Whoopie Creek Bridge(NFS Road 384) near Spar Lake in the Troy District, and Keeler Creek took out the Lake Creek Road county bridge(NFS Road 473) and the county levee in Troy. Additional washouts occurred on Libby Creek Road (NFS Road 231) at mileposts 0.9 and and about 25.0 and along NFS Road 384 where it was washed out due to a landslide past the Whoopie Creek Bridge. The Hiatt Creek Bridge(NFS Road 384) near Spar Lake sustained damage. While the Ross Creek bridge survived the flood, the creek bed beneath it rose significantly. Floodwaters deposited so much rock and gravel that the space under the bridge was reduced from 8 feet to 6 inches, leaving no room for water to pass. The West Fisher Road lost about 600 feet of road at milepost 25.5, and the Poorman Creek culvert washout on NFS Road 278/Bear Creek Road. The Upper Young Creek Road, NFS Road number 7202, located northwest of West Kootenai, was made impassable between milepost 3.5 and 3.6 due to a landslide. The Kootenai National Forest Service remarked that there were other bridges that incurred minor damage and they will have to repair some of the abutments.

In the Ross Creek Cedars recreation area, the newly reconstructed facilities and trails completed just months prior at a cost of approximately $1.9 million sustained major damage. The access route, NFS Road 398, was compromised by multiple landslides and debris deposits, including a large slide that taken half the road and a compromised bridge where Ross Creek Road crosses Ross Creek.

In Libby, Cherry Creek jumped its banks to flood subdivisions along Cherry Creek Drive and Claire Avenue, while Libby Creek inundated homes near Champion Haul Road and Riverdale Drive, cutting off residents and submerging properties under nearly a foot of water on Vicks Lane. The Lower Flower Creek Diversion Dam was nearly compromised by debris and high sediment, resulting in a long-term boil water advisory for the City of Libby. For a time, the 5th Street Bridge in Libby was under water. Water was also across the road on West 2nd Street Extension by Parmenter Creek.

In Troy, Callahan Creek washed away a 15-foot rock barrier, and Iron Creek caused flooding in multiple residences. Road 427/Callahan Road had 2 washouts (3.4 mile and 6 mile). Washout on road 473/Keeler Road. The Poorman Creek SNOTEL, located in the Cabinet Mountains south of Libby, reported 5.10 inches of rainfall in 24 hours. This marked the wettest 24-hour period within the month of December, and the third highest for any time of the year. The Yaak River near Troy crested at 8.3 feet(7,940 cubic feet per second) at 1130MST on December 11, while the Fisher River near Libby reached 7.67 feet(4,710 cubic feet per second) at 2115MST.