Thunderstorm Wind in Flathead County, Montana

The weather sensor at the Kalispell International airport reported a gust to 55 mph, and heavy rain with reduced visibilities as low as one mile for at least 19 minutes. It reported 0.27 of rainfall in 23 minutes from 4:32 to 4:55 pm MDT. As the gust front moved through the Kalispell area, there were reports of a dust storm that brought visibilities down to near zero for several minutes before the rain began. The dust cloud moved through an open door of the Glacier High School setting off fire alarms and filling the school with dust. The school's custodial staff had to spend the night removing and cleaning the dust out. The strong wind caused large trees to fall, knocking down power lines and blocking roads. The power company reported approximately 2,500 people without power for a time that evening.

As an upper level low approached the Pacific Northwest coast, a mid-level jet maximum of 40 to 50 knots triggered a line of thunderstorms that moved from eastern Oregon into the Idaho Panhandle. As this line continued to track east-northeast, they formed a gust front triggering even stronger storms over western Montana that brought strong gusty winds, frequent lightning, heavy rain and damage. The lightning detection network reported over 1500 strikes during the event.