High Wind in Cascade County Below 5000ft, Montana

Many sensors measured gusts of 58 mph or greater or sustained winds of 40 mph or greater averaged over at least an hour, including Montana mesonet stations Belt NW, Sun River SE, Benton Lake W, and Eden NW, ASOS/AWOS stations KGTF Great Falls Airport, K1IM India, K1AM Alpha, and KGFA Malmstrom Air Force Base, as well as mesonet stations FW1843 Great Falls (10 WSW Stockett) and FW5493 Vaughn (1 WSW Sun Prairie). TH epeak observed gust was 75 mph at the Belt NW Montana mesonet station.

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.