Avalanches, even the big ones, aren’t particularly thunderous like you’d hear in a movie theater with Dolby Surround.

They make more of a swooshing sound.

“One thing you do hear is the timber snapping like matchsticks,” says Paul Baugher, Ski Patrol director at Crystal Mountain, the resort 90 miles southeast of Seattle.

He was there late Monday afternoon when an avalanche triggered for safety reasons didn’t go quite according to plan.

As the snow descended a vertical 1,000 feet, down went something like 100 trees each between 1½ to 2 feet in diameter, as well as a chairlift bolted onto a 6-foot concrete base. No one was hurt.

“Once the freight train leaves,” says Baugher about the avalanche, “it leaves a pathway of destruction. It was a huge area, four or five football fields wide. Tons upon tons of snow, in some places 30 feet deep.”

Baugher says it was the worst avalanche recorded on that path since the resort opened in 1962.

“The engine room and the base terminal had been moved 20 to 30 feet,” says Baugher about the chairlift.

He figures it will cost up to $2 million to replace it.

In addition, he says, the avalanche also bent but didn’t destroy another three or four towers from what is called the High Campbell chairlift system.

He estimates that on a scale of 1 to 5, this was a size 4 avalanche.

Size 5 is the worst, capable of taking out entire villages, of which over the centuries there is a long list.

Size 4, according to the Canadian Avalanche Association, typically has a mass of 10,000 tons and can “destroy a railway car, large truck, several buildings.”

Baugher says the Monday avalanche was at a slope called “The Throne,” popular with “double black diamond” expert skiers.

So, says Baugher, too bad about the chairlift, “but this is one of the unintended consequences of the lengths we go to protect humans.”

Baugher was there, with the resort closed, when three women on the ski patrol tossed a 25-pound packet of ammonium-nitrate explosive with a 90-second fuse. They made sure to be on the other side of the ridge when the explosive went off.

The idea is to intentionally trigger an avalanche when the area is cleared of people as the snow is becoming unstable, but before it slides.

But, Baugher says, obviously the triggered avalanche “was much bigger than one would have expected.” It was, he repeats, “historic” for that slope.

The past few weeks of weather have made our mountains particularly susceptible to avalanches. The Associated Press has reported that 17 people have died in avalanches this winter in the Cascades and Rockies, 11 of them since early February.

Several feet of new snow meant renewed skiing, but it also meant this new snow was sitting on top of weak layers of old snow.

“It’s like having a layer of ball bearings or … a house of cards,” says Benj Wadsworth, nonprofit executive director of the Northwest Avalanche Center.

Not wanting to take a chance, Baugher and his crew began triggering the avalanches.

The resort says it’s already getting messages from fans to buy one of its 60 to 75 chairs; the whole thing will be replaced this summer.

The last time the resort sold chairs from a decommissioned chairlift system was in 2011, says Tiana Enger, director of marketing. More than 100 chairs were sold at $250 each.

“And we had a waiting list of 100,” she says. “People want chairs as a little piece of history from the mountain and turn them into a swing or a chair to put on the front porch.”

Enger says that this time, money from the chair sales probably will be donated to the Ski Patrol. Certainly, with handling 25-pound packs of explosives, the guys have earned it.

Times researcher Miyoko Wolf contributed to this report.

Erik Lacitis: 206-464-2237 or elacitis@seattletimes.com Twitter @ErikLacitis