Flood — Musselshell, Montana

2011-05-23 to 2011-05-31 · near Roundup Arpt, Musselshell, Montana

Event narrative

Persistent heavy rainfall combined with snowmelt in the mountains resulted in extensive and significant flooding along the Musselshell River and its tributaries, including the Roundup area where record flows were observed. The Musselshell River at the gauge at Roundup crested at a record of 14.78 feet on May 26th. As the water on the Musselshell rose quickly on the 26th, floodwaters quickly inundated the town of Roundup. Portions of Highways 12 and 87 were closed in and around Roundup with up to 8 feet of water covering the roads in spots. This completely cut off the town from surrounding areas for several days. Homes and businesses in Roundup were inundated by flood waters with water up to rooftop levels in some cases. 39 homes experienced major damage and were complete losses. Another 110 homes and businesses experienced at least minor flood damage. Four teenagers were rescued from the high waters after they disobeyed orders to stay out of the area and then became stranded. Further downstream on the Musselshell River, another 14 homes were damaged by the flood in the town of Musselshell. In all, hundreds of families were isolated due to the floodwaters and severely damaged roadways. Railroad tracks were reported as washed out in spots. Musselshell County was reported as one of the worst hit counties in the state of Montana.

Wider weather episode

A Pacific low moved into the four corners region on the 17th and migrated northeast into the Dakotas through the 22nd, bringing another round of heavy precipitation aided by a tap of Gulf of Mexico moisture. Another system passed to the south on the 23rd and 24th, continuing the precipitation across the area. These two systems brought a total of 4 to 7 inches of precipitation to the area through the 25th. From May 29th through May 31st, another Pacific storm system moved northeast through the Billings Forecast Area, producing a half inch to 2 inches of precipitation across the area. A few areas received close to 3 inches of precipitation. The culmination of precipitation events resulted in historic flooding across the Billings Forecast Area.

Flooding along the Musselshell River began on May 24th and continued through the end of the month. There was extensive flooding in Harlowton, Ryegate, Lavina and Roundup. Highways 87,12 and 3 into these towns were inundated and closed. Evacuations occurred in Wheatland and Golden Valley Counties, and about 30 homes were evacuated in Roundup in Musselshell County. About eight feet of standing water surrounded the Busy Bee Cafe, a local landmark in Roundup. Houses and businesses in Roundup continued under several feet of water through May 30th.

View location on OpenStreetMap → (46.6857, -108.9341)

Source: NOAA Storm Events Database, event_id 308867. Narrative written by the NWS forecast office that issued the report.