High Wind in Fergus County Below 4500ft, Montana

Numerous sensors in this zone measured sustained winds of 40 mph or greater averaged over at least an hour or gust of 58 mph or greater, including Montana mesonet sensors Coffee Creek N, Christina W, Forestgrove N, Roy E, and Winifred NE, AWOS/ASOS sensors KLWT Lewistown Airport, K1EM Echo, K1OM Oscar, K1NM November, KMVH N Bar Ranch, and K1DM Delta, mesonet sensors MTDEN Denton (MT DOT), MTBOH Bohemian Corner (MT DOT), MTBCH Beacon Hill (MT DOT), and RAWS sensor ARMM8 Armells Creek. Public reports were received of shingles blown off of roofs, in addition to power going in and out all day near Denton. The peak gust in this zone was 87 mph at Beacon Hill in SE Fergus county. Of particular note, sustained winds averaged 53 mph at Beacon Hill between 145 PM 12/17 and 1 AM 12/18.

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.