Flood — Lincoln, Montana

2025-12-11 to 2025-12-12 · near Yakt, Lincoln, Montana

Event narrative

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.

Wider weather episode

Record precipitation fell as a prolonged atmospheric river event gripped the region from December 6 through 12. Much like a garden hose being moved back and forth, the jet stream shifted the focus of this moisture plume across the Pacific Northwest, repeatedly drenching parts of northern Idaho and western Montana. Between December 10 and 11, 2025, the atmospheric river specifically focused on northwest Montana, and produced record rainfall and catastrophic rain-on-snow flooding. A saturated snowpack acted as a sponge until reaching capacity late December 10, when warm nighttime temperatures and rainfall rates of 0.30-0.50 inch per hour below 7,000 feet triggered rapid runoff. Total precipitation amounts ranged from 4 to 7 inches within the 24 hours leading up to the event.

Significant flooding and landslides occurred across Lincoln, western Sanders, and western Mineral Counties, where numerous tributaries and streams overwhelmed their banks. The event resulted in eight bridge washouts in Lincoln County, with one additional bridge lost in both Mineral and Sanders Counties. This was one of the most significant rain-on-snow December events since 1933, when 12 bridges were washed out in Lincoln County alone. On December 11, Governor Greg Gianforte issued Executive Order 9-2025 declaring a flooding disaster in northwestern Montana. Following a formal request on December 16, a Presidential Emergency Declaration was approved to provide federal aid for Lincoln and Sanders counties and the Blackfeet Nation. Preliminary assessments placed infrastructure and property damage at $35.1 million for all three counties. The only injury was from a man who drove off the Farm-to-Market Road bridge into the waters below. He was able to escape with only scrapes and bruises. This atmospheric river event also brought high winds to the mountains and a few valley locations. Precipitation levels reaching 238 percent of normal in British Columbia and the Glacier Region sent inflows into Flathead Lake soaring to over 300 percent of average. The West Central Montana Avalanche Center reported several wet loose avalanches and mudslides near steep highway cuts near Lolo Pass on December 11. They reported that the highway crew had to clear debris from the road. Rockfall was also reported along MT-1, north of Georgetown Lake.

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Source: NOAA Storm Events Database, event_id 1304729. Narrative written by the NWS forecast office that issued the report.