A brief but powerful storm with winds up to 55 mph roared across the valley Thursday evening, which blew in first as a dust storm before taking down trees and power lines, knocking out power for roughly 2,500.

The storm came in at 4:25 p.m., striking particularly hard at Glacier High School.

An email from Principal Callie Langohr related that dust set off fire alarms at the school.

“We got our athletes off the practice fields and safely into the GHS building. As a result of opening the doors to the building to let our students in, the dust rolled into the building and set off the fire alarm,” Langohr wrote. “Our fire system is extremely sensitive to smoke, dust, helium balloons etc., and we had a major cloud of dust inside the facility.”

The dust storm cut short an intrasquad scrimmage for Glacier boys soccer teams. The scrimmage was underway when the wind-driven dust hit, reducing visibility to zero and forcing spectators and players to scramble to vehicles or hunker down on the field to ride out the storm.

The school’s custodial staff was set to focus on dust removal and cleaning throughout the night Thursday so today’s school day would not be affected.

Wind gusts reached 55 mph at Glacier Park International Airport and 45 mph at Sheepherder Hill west of Kalispell.

As the full force of the storm hit the valley, large trees were downed, blocking roads and knocking down power lines.

The worst tree-fall seems to have occurred on Kokanee Bend, where law enforcement scanner traffic indicated a tree had fallen on a home and cut it in half, trapping people inside. The people were uninjured and were eventually able to get out of the house.

Flathead Electric Cooperative’s online outage viewer indicated roughly 740 members without power as of 5 p.m., climbing to 2,000 within 10 minutes and reaching nearly 2,500 by 6:30 p.m.

Fire crews scrambled to a variety of emergency calls ranging from grass fires to downed  trees and power lines.