High Wind — Snowy and Judith Mountains, Montana

2025-12-17 · Snowy and Judith Mountains, Montana

Event narrative

This zone does not have many sensors, so verification is a bit sparse. The one DOT sensor at Lewistown Divide lost power and did not report winds/gusts for the overwhelming majority of the event. The other reliable sensor is Judith Peak RAWS JPKM8, though that sensor is at a mountain peak. Given these factors, the source for this verification is a single Ambient Weather sensor which measured a 59 mph gust southeast of Lewistown. If you were to include Judith Peak, the peak observed gust in this zone was 94 mph and the duration of the event would expand through much of the day December 17.

Wider weather episode

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.

Source: NOAA Storm Events Database, event_id 1303834. Narrative written by the NWS forecast office that issued the report.