MISSOULA — Damage was minimal, but the magnitude 5.8 earthquake centered south of Lincoln early Thursday was the most violent yet in Montana west of the Continental Divide.
It nosed out the 5.7 quake that struck the Swan Range south of Bigfork on April 1, 1952, and a 5.5 tremor in September 1945 that shook what later became the Bob Marshall Wilderness.
Montana’s most destructive quakes have occurred farther east. The deadliest and strongest at 7.5 triggered a landslide above Hebgen Lake that killed 28 campers near Yellowstone National Park just before midnight on Aug. 17, 1959. It created a new lake on the upper Madison River called Quake Lake.
In late June 1925, brick school buildings in Manhattan, Logan, Three Forks and Lombard were ruined when the state’s second-worst quake at magnitude 6.9 hit near Townsend. And a series of quakes in the fall and winter of 1935, the largest a 6.3 on Oct. 19, caused four deaths and $4 million in property damage in Helena.
Don’t make too much of the paucity of major seismic events in the Columbia River drainage, said Rebecca Bendick, a geologist and associate professor at the University of Montana.
There’ve been devastating quakes on this side of the mountains since the last ice age, just none when people roamed these parts.
“It’s possible, for sure, but it is not probable in our lifetime,” Bendick said. “These events happen so infrequently in time in terms of how long humans live.”
And just because we’ve had a moderate event like the one high on the divide near Stemple Pass on Thursday, “it has no impact on the likelihood of another event,” Bendick said.
Though it quickly became a major social media attraction, the earthquake and its aftershocks disrupted little in western valleys.
Missoula Fire Chief Jason Diehl said his department received only one related call. An elevator in Missoula Manor quit working and went into seismic mode. MFD couldn’t fix it, so an elevator tech was called in. No one was trapped in the elevator.
“That was pretty much the extent of it on our end,” Diehl said, adding, “I was a little worried about the pharmacy building” at the former Missoula Mercantile site. It, too, was unscathed.
Sgt. Travis Welsh, public information officer with the Missoula Police Department, said there were no reports of injuries or major property damage from the earthquake.
“We had lots of people calling in here to our non-emergency line, wondering what we could tell them about what happened, which at the time wasn’t much,” Welsh said.
In the event of an incident like an earthquake, officials ask people not to call 911 unless they require immediate assistance.
Adriane Beck, director of the county’s Office of Emergency Management, said the Missoula 911 Center received 154 calls in the hour after the quake shook the area at 12:30 a.m., a figure she termed “significantly higher” than what would usually be seen at that time of night.
“It certainly didn’t overwhelm our lines or anything. Some people were calling to let us know there had been an earthquake. A lot of people were calling in saying they didn’t really know what was happening,” she said.
Butch Larcombe, spokesman for NorthWestern Energy, issued a statement Thursday that the company had not found any damage to its electrical or natural gas systems across the state. The earthquake did cause a power outage in the Lincoln area that was fixed within 45 minutes.
Missoula County Public Schools reported no immediate safety concerns at the district schools, including those undergoing construction.
Hatton Littman, the district’s director of technology and communications, said all renovations to the schools are being done with earthquake safety considerations in mind. Prior to the 2015 passage of the Smart Schools 2020 Bond Project, engineers assessed the schools for how the structures would survive a severe earthquake. Earthquake safety upgrades were worked into the cost of the projects, Littman said.
The issue of earthquakes causing damage to public buildings is something the district became concerned about after Central Elementary in Helena had to close down in 2013, when a structural engineering report revealed a quake would cause serious structural damage. It is imperative to check the condition of structures following a seismic event in order to assess their integrity for public safety, according to the U.S. Geological Survey.
The school district will make a plan for a more thorough assessment of its buildings on Monday, Littman said.
Eric Hoover, Ravalli County’s Disaster Emergency Services Coordinator, said no reports of infrastructure damage were received.
“We’ve been in communications with our partners from the state about potential impacts on our dams,” Hoover said. “There have been inspections of the Painted Rocks and Lake Como dams, but there doesn’t seem to be any findings of any issues.
“The impacts were more severe the closer you get to the Lincoln area,” Hoover added. “We were monitoring the situation throughout and we were ready to implement whatever part of our emergency management plan that was necessary.”
In the Flathead, the earthquake left frayed nerves but no damage. Rick Sacca, Flathead County’s emergency management director, said the dispatch center in Kalispell received 76 calls from people anxious to report they had felt the earthquake.
“As of right now, we have zero injuries and zero reports of damage,” Sacca said at about 9 a.m. Thursday. “I’m pretty happy about that.”
Steve Stanley, Lake County’s emergency management director, said that county’s dispatch center was also overwhelmed by calls.
“It shut us down for awhile,” he said. “I don’t know how many calls we received, but it was a lot. There were no requests for service.”
At his home in St. Ignatius, Stanley said the earthquake was strong enough to send his daughter and their children under a table.
“They are visiting from Alaska,” he said. “That’s the thing they do up there.”
The earthquake didn’t appear to cause any damage at the Selis Ksanka Qlispe Dam, five miles southwest of Polson, said Energy Keepers CEO Brian Lipscomb.
Workers began checking the dam immediately following the earthquake and were continuing that process Thursday morning, Lipscomb said.
Glacier National Park spokesperson Lauren Alley said there was no confirmed damage at the national park.
There was a power outage for a small portion of the park. It was small enough that visitors may not have even noticed. It’s also not clear if the outage was caused by the earthquake, she said.
This story contains reporting from the Missoulian's Perry Backus, Ashley Nerbovig, Peter Friesen and Dillon Kato, and Richard Rowan of the Ravalli Republic.