High Wind in Eastern Glacier, Western Toole, and Central Pondera, Montana

Numerous sensors reported sustained winds of 40 mph or greater averaged over at least an hour, or gusts of 58 mph or greater, including Montana mesonet stations Mission Lake S, Buffalo Lake E, Ethridge N, Sunburst NW, and Conrad N, ASOS station KCTB Cut Bank Airport, AWOS station KSBX Shelby Airport, mesonet stations BFAM 12 W Cut Bank, MTVAR Valier Junction I-15 (MT DOT), GW1987 Ethridge 3 SE, MTSUN Sunburst (MT DOT), GW0664 Shelby Airport, DW0975 Kevin, MTSWT Sweet Grass (MT DOT), and FW8513 Sunburst. The peak observed gust was 88 mph at Mission Lake S. Several instances of sustained winds averaging 50 mph over at least an hour were observed along Interstate 15.

Robust low to mid level flow westerly flow associated with a potent shortwave and attendant cold fronts resulted in a prolonged period of high-end winds and gusts across the entire region Dec 17 into the 18th. Multiple gusts in excess of 90 mph were observed in populated areas, with a peak observed gust of 104 mph west of Bynum. Prolonged power outages were observed across the region, mostly due to trees being damaged/falling over completely. Additional societal impacts included extremely difficult to impossible travel conditions, which prompted a Civil Emergency Message for areas along the Rocky Mountain Front the afternoon of the 17th.