High Wind in Gallatin Valley, Montana

Several sources reported sustained winds of 40 mph averaged over at least an hour or gusts of 58 mph, including ASOS station KBZN Bozeman Airport, Montana mesonet station Manhattan S, mesonet station AV387 Manhattan, as well as trained spotters. The peak gust in the Gallatin valley was reported by a trained spotter 1 NW of Amsterdam, who measured a 78 mph gust. Additional damage reports include 100-foot pine trees being snapped and blown over and portions of 8-feet fences being blown away completely.

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.