Hail in Sweet Grass County, Montana

Several severe thunderstorms moved across the Billings Forecast Area during the late afternoon into the evening hours of the 31st. The most notable severe thunderstorm moved across the Roundup area. This thunderstorm produced very large hail along with flash flooding. A damage survey was conducted which found that a majority of homes and businesses within Roundup experienced some type of hail damage. Damage was to the north and west facing aspects of homes and businesses with numerous broken windows and pitted siding and fencing. Six county buildings along with the hospital and high school were damaged. Approximately 40 to 50 percent of the local businesses were damaged. In addition, 100 percent of vehicles and campers left in the open were damaged with dents or windshields broken. Trees were stripped of leaves.

Flooding also occurred across town and portions of the surrounding area. Highway 87 had several areas where debris had washed over the road from floodwaters. Main Street through Roundup was similar, with low lying areas (in and around the Busy Bee Cafe) being flooded. In addition, Bender Road was washed out between Log Cabin Road and County Road #4. The peak river stage of the Musselshell River at Roundup was around 11.5 feet, a foot and a half above flood stage and the sixth highest crest on record. One home was evacuated due to being surrounded by floodwaters.