A massive avalanche that thundered down Mount Shasta earlier this month is being called possibly the largest in the mountain’s recent history.
The natural avalanche occurred off Casaval Ridge between the afternoon of Feb. 13 and the morning of Feb. 14. According to the Mount Shasta Avalanche Center, the avalanche likely began near the 12,000-foot elevation of Shasta — its summit elevation is 14,162 feet — and flowed on the southeast side of the mountain to the 7,200-foot level down Avalanche Gulch, about 5,000 vertical feet and a distance of more than three miles.
Avalanche Gulch is alongside the mountain’s most popular south side climbing route, sometimes called the Climber’s Gully. Mostly climbs are done between June and September.
To Bunny Flat
According to the Avalanche Center, the avalanche began near The Heart and Thumb Rock down to Lake Helen, a mid-mountain campsite, down toward Horse Camp, where most climbers camp overnight before making early morning summit attempts. Horse Camp was not damaged. The run-out extended south to near the Bunny Flat Trailhead.
There reportedly were no climbers or backcountry skiers in area and no reports of injuries. The Mount Shasta Ski Park, which is east of the avalanche path, was not impacted and has remained open for skiers and snowboarders.
“There’s a reason it’s called Avalanche Gulch,” noted a ranger with the Shasta-Trinity National Forest.
“It must have just been flying down there,” said Steve Lewis, who has climbed Shasta more than 40 times and snowshoed along the avalanche path a few days after the event. “It must have been hauling ass down the mountain.”
Lewis, author of “Climbing Mt. Shasta,” a now out-of-print guidebook for beginning Shasta climbers, said he compares this month’s avalanche to one in 1996, calling both “monster” events.
“This was much deeper than the ‘96 one,” he said. “This one cut deep into the gulch.”
Lewis seconded reports from the Avalanche Center, which said the debris pile created by the surging snow is more than 30-feet high, up to 60 feet deep and up to 1,500 feet wide. He said there were 10- to 15-foot dropoffs.
It’s speculated the main avalanche could have caused the release of other avalanches on Casaval Ridge, Trinity Chute, The Heart and Sargents Ridge. Some large trees were buried and carved by avalanche debris. The Avalanche Center report noted Shasta received several feet of fresh snow in less than 24 hours beginning Feb. 13 followed by rapid warming that resulted in rain and mist the following day.
“This new snow was plastered onto a complicated snowpack with cold dry surface snow from a storm on the weekend of the Feb 9 and 10,” according to the Avalanche Center website. “Most of the storms in February have been associated with periods of strong northerly wind continually loading the upper Casaval ridge area. The wet, heavy snow from Wednesday the 13th plastered enough snow to cause this large slide that likely stepped down into deeper weak layers, entraining more and more snow as it gouged its way down the nearly 5,000-foot run and depositing 30-plus feet of snow in the climber’s gully (Avalanche Gulch proper) down to 7,200 feet.
The avalanche was rated as a D4, or powerful enough that it could destroy a railway car, large truck, several buildings and/or a substantial amount of forest.