Flood — Yellowstone, Montana

2011-05-21 to 2011-05-26 · near Mossmain, Yellowstone, Montana

Event narrative

Widespread rainfall of 2 to 3 inches with locally higher amounts fell across the Yellowstone County area during a two day period. Billings had its all-time daily rainfall record broke on May 24th with 3.12 inches. This was just a part of a record setting precipitation month for Billings which totaled 9.54 inches. This rainfall on top of an already wet month resulted in some streams and creeks over Southern Yellowstone County to overflow their banks. Flooding occurred on Blue Creek in the Briarwood area. Several homes and structures were surrounded by water on Aviemore Court where some voluntary evacuations occurred. In addition, the Briarwood Golf Course was inundated with water.

Pryor Creek was out of its banks resulting in water spilling over a dike in a low lying area of Huntley. Fly Creek near Pompey was out of its banks and flooded a roadway leading to town. Flooding occurred along most of Pryor Creek between the towns of Pryor and Huntley. In addition, county officials reported that Pryor Creek Road Bridge between Interstates 90 and 94 was washed out.

Blue Creek Subdivision at Jene Helene Avenue flooded many homes and the Briarwood Golf Club May 20th-22nd. This resulted in the Billings Fire Department issuing voluntary evacuation orders. In addition, flash flooding occurred in Billings on May 24th forcing many road closures downtown and causing large boulders to fall off the Rimrocks. Flooding from Pryor Creek inundated a Huntley neighborhood and destroyed Pryor Creek Road on May 22nd.

The Yellowstone River at Billings went above flood stage on May 25th through May 26th. The river crested at 13.92 feet on May 26th.

In addition, a man operating a backhoe trying to save his house, drowned near Pryor Creek. The roadway had washed out from underneath the backhoe.

Damage estimates based on FEMA reviews and Individual Assistance approvals.

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. A new all-time daily precipitation record for Billings was set on May 24th. 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. The monthly precipitation for May resulted in the wettest May ever recorded in Billings.

Widespread, severe flooding occurred across the entire Billings Forecast Area. Many roads and bridges were damaged or washed out across the area, including closure of I-90 between Livingston and Springdale eastbound lanes. The Montana Department of Transportation alone estimated over $36 million in damage to state and federal highways across the state of Montana. Hundreds of homes and trailers and multiple businesses experienced flood damage. There was damage to flood control dams. On May 19th, Montana Governor Brian Schweitzer declared an emergency for the state. In addition, the Governor requested that the President declare a major disaster for the State of Montana on June 1st, as a result of substantial widespread flooding. Governor Schweitzer deployed the Montana National Guard in Roundup and Crow Agency to help with flood response efforts May 28th and 29th. Flood emergencies were declared by the Governor for all but three counties in the Billings Forecast area. Emergency declarations included the Crow Reservation in Big Horn County. There were two fatalities, an elderly woman in Boyd in Carbon County fell into a flooded ditch and was swept away, and a man from Huntley in Yellowstone County was killed on an excavator when flooding from Pryor Creek overtook him. Multiple Emergency Operation Centers and Incident Commands were set up across the area, including in Billings in Yellowstone County, and in Park County to coordinate flood relief and response efforts.

A persistant upslope northeast flow into the region resulted in another round of locally heavy rainfall again on May 29-30th. An additional 1-2 inches of rainfall were noted, especially for the Beartooth and Big Horn Mountain foothill areas. This resulted in prolonged or even renewed flooding in some locations through the end of the month.

View location on OpenStreetMap → (45.6565, -108.5016)

Source: NOAA Storm Events Database, event_id 313379. Narrative written by the NWS forecast office that issued the report.