A line of thunderstorms grinding up the Bitterroot Valley converged over Missoula on Monday evening, spawning gusts up to 74 mph that toppled century-old trees and flipped pole barns off their foundations.
About 18,000 people from Darby to Polson were without electricity for several hours as the storm moved south to north.
At one point around 6:30 p.m., emergency service personnel were responding to 25 calls at once. That included a grass fire that raced from the Airway Boulevard exit off Interstate 90 north to the top of Goodan Lane, missing a dozen houses by a few hundred yards before being contained.
“With the fire moving like it was, we went to this one first,” Missoula Rural Fire Battalion Chief Greg Orr said, while dispatching teams of firefighters to several more reports. “Every single fire department is stretched thin. We’ve got a dozen units up here.”
On the valley floor, microburst winds hammered Missoula’s western neighborhoods with karate-chop blows. In the Benson’s Farm cornfield along Reserve Street, a gust crushed a path through the stalks like a runaway semitrailer – more than 100 yards long, but just 15 feet wide.
Farther west, a pole barn big enough to hold several recreational vehicles and other equipment was flipped upside down into the roadway near the intersection of South Seventh Street West and Hiberta Street.
“I didn’t see it, but I heard it,” across-the-street neighbor Pat Danishetsky said of the wreckage. “This tree went first, and then another one on the other side of that duplex. I couldn’t see anything because of all the dust blowing. Then there was this loud – super loud – snap and crack. I thought it was lightning at first, because then the power went out.”
Danishetsky’s home was mostly untouched, but a block away, Bob Hall couldn’t find his 10-by-12-foot metal shed.
“It’s completely gone,” Hall said, looking at the top of a spruce tree that had snapped off and smashed through the ground-floor window of his two-story house. “I had just got off work and saw this coming. I put the dogs in the Jeep and the tree came down.”
“Are you missing a shed?” neighbor Doug Johns said from the street. “It’s almost at the neighbor’s house back there (a city block away). It’s pretty flattened.”
Falling trees knocked down power lines that left much of Missoula west of Higgins Avenue without lights. The blockage also hindered residents who were trying to leave the area to stay in hotels for the night because of gas leaks and damaged homes.
Van Buren Street north of Interstate 90 was blocked by a downed tree that cut off one of two access routes into the Rattlesnake neighborhood. The Greenough Drive and Lolo Street accesses remained open, but Missoula police warned of many downed power lines in the Rattlesnake Valley.
Another downed power line was blocking traffic in the Linda Vista neighborhood between the 4800 blocks of Scott Allen and Christian drives. The line was not charged Monday evening, but was hanging across trees and lawns in the area.
The Missoula chapter of the American Red Cross opened a temporary shelter for people displaced by the storm at Christ The King Catholic Church, 1400 Gerald Avenue.
On South Third Street West by Harriet Street, Dick Houldson had two big spruce trees ripped out by the roots next to his home. Fortunately, they fell due north, blocking the street but missing his house.
“I’ve lived here for 40 years,” Houldson said. “I haven’t ever seen a storm come through like this one.”
Across the street, Larry Brumback was soon frustrated with the motorists who insisted on driving over his yard to get around the trees.
“Bunch of people with big trucks and young attitudes decided ‘I’ll just drive right over that,' ” Brumback grumbled. So he grabbed a chainsaw and cleared a lane through the timber. Another neighbor rolled up with a Bobcat front-end loader and pushed the logs clear.
Missoula city forestry crews were already at work Monday evening removing fallen tree debris. City officials asked that debris that is not blocking streets or sidewalks be reported to the Parks and Recreation Department on Tuesday by calling 721-7275. Avoid any trees that may be touching utility wires.
NorthWestern Energy spokesman Butch Larcombe said falling trees appeared to knock over some transmission lines, which carry large amounts of electricity to whole neighborhoods or communities.
But the utility didn’t suffer any lightning strikes to its substations or other equipment. About 15,000 customers were in the dark in Missoula, with another 3,000 people affected from Darby to Philipsburg.
“I’m betting it’s going to be tomorrow morning before everything is back on,” Larcombe said. “It’s going to take all night to work through them all.”
The first reports of strong winds came around 5 p.m. when a volunteer weather spotter clocked a gust of 51 mph near Darby.
“The line of storms kept going straight up the Bitterroot, and when it got over Missoula, those thunderstorms converged,” National Weather Service meteorologist Genki Kino explained. “That helped increase our winds. We had reports of 50 to 60 mph in the Bitterroot, but the peak wind gust in Missoula was 74 mph. And we had sustained winds of 59 mph. That’s pretty impressive.”
Kino said the thunderstorms reacted to the dry, warm valley floor by dumping blocks of cold air from their cores straight down on the city. Those outflow winds, also known as microbursts, can cause intense but highly localized damage.
“By 7 p.m., it had tapered off,” Kino said. “We got reports of 45 mph winds in Polson.
At least one fire was burning near a Polson subdivision near Lone Lake Drive. And in the Bitterroot, U.S. Forest Service firefighters were responding to at least 10 new fires after the storm passed through.
Four of those fires were in the Stevensville Ranger District near Burnt Fork Lake. A helicopter with a water bucket was making drops on the fire until dusk, and ground crews were en route, according to Bitterroot National Forest spokeswoman Joni Lubke.
Two more starts were in the Darby/Sula Ranger District, including one in Lost Horse Canyon and one at the Lost Trail Powder Mountain ski area. Three other fires were reported near Benson Creek, Martin Creek and Whisky Gulch.
All the fires were believed to be smaller than a tenth of an acre.