Hail — Valley, Montana

2007-06-16 · near Nashua, Valley, Montana

Event narrative

One hundred percent of the businesses and homes in the town were damaged from the combination of large hail and damaging winds. Many vehicles also had significant damage. Damages included roofing, windows, gutters, siding, trees and gardens. See entire episode narrative for full details.

Wider weather episode

During the late afternoon and evening of June 16, 2007, a high precipitation supercell thunderstorm tracked from across northern Montana, just to the north of a warm front. This was the most devastating hail storm to affect the area since at least 1999, and prompted 22 severe thunderstorm and 6 tornado warnings in the NWS Glasgow county warning area. The storm began early in the day just east of Glacier National Park and gradually moved hundreds of miles eastward through the day. By 3 pm, the storm crossed into the NWS Glasgow area in Phillips County, where it started to make a turn to the southeast. The storm traveled for over 250 miles before decreasing in Richland County near the North Dakota border a little after 11 pm. Hail up to baseball size and wind gusts in excess of 85 mph accompanied the storm. Torrential heavy rainfall was also experienced, prompting seven flash flood warnings to be issued. The large hail left a hail swath seen on GOES and Terra MODIS satellites that had a path at least 225 miles long, and up to 12 miles wide.

The most significant damage from the storm occurred in portions of Valley and McCone Counties. The towns of Glasgow and Nashua, both in Valley County, took a direct hit from the storm. In Glasgow, southeast winds gusting to 60 to 65 mph ahead of the storm switched into the northwest with gusts in excess of 70 mph. Golfball to baseball sized hail fell for several minutes before diminishing to penny sized for another 10-20 minutes. The majority of the homes and businesses in Glasgow had some sort of damage including: broken windows, damaged shingles, dented or broken gutters and skirting. Many vehicles also had significant hail damage. Just the property damage alone in Glasgow was nearly $8.0 million dollars. As the storm continued east it hit the town of Nashua and every home and business had some form of damage from the baseball size hail and the damaging winds that occurred with it. The winds were measured at 89 mph just west of town. Property damage was estimated to be $3 million dollars.

In rural areas outside of Glasgow and Nashua there were several cottonwood trees completely uprooted. Horses and cattle were injured by the hail and wind, and Montana Fish, Wildlife and Parks reported many birds and small animals were killed by the hail. There were thousands of acres of alfalfa, wheat, and corn that were completely destroyed. At this time, damage estimates to crops in Valley County are at $20 million dollars.

The storm also produced heavy rainfall of 1 to 2 inches, and was followed later in the evening by additional heavy rain. Rainfall of 2 to 7 inches fell in the Antelope, Brazil and Willow Creek basins. The Antelope Creek basin had its most significant flood on record and one road was completely underwater for nearly a third of a mile. One ranch was isolated by the flood waters for three days.

As the storm continued across northern McCone County and into western Richland County it continued to produce hail up to the size of ping pong balls and wind gusts that were estimated as high as 80 to 90 mph knocked down telephone and electrical poles. There was significant damage to farms and ranches in the Vida area, as well as significant loss of crops, estimated at $5 million dollars. The rural nature of the area minimized the property damage that could have occurred.

The overall estimated damage in this storm between the hail and wind damage, and the subsequent flooding is 34.2 million dollars.

View location on OpenStreetMap → (48.1300, -106.4150)

Source: NOAA Storm Events Database, event_id 27893. Narrative written by the NWS forecast office that issued the report.