A large avalanche apparently triggered by a group of skiers on Monday left behind crowns more than seven feet tall as it ripped down Mount Ben Stewart, beyond the boundary line of Eaglecrest Ski Area.
A group of people had skied that terrain previously, said Southeast Alaska Avalanche Center Executive Director Tom Mattice.
It appears the skiers were close enough to create a “sympathetic release” and trigger the avalanche after they had left the area, he said. It ran down the mountain and across a trail people use to access it.
That avalanche, that occurred around 2 p.m., was the larger of two that happened on Stewart that day — the first ripped down an area riders call the Stewart Headwall and the second below a band of cliffs located lookers-left of a large bowl feature commonly called Wedding Bowl.
Juneau resident Jesse West, 23, got a front row seat that day. He was one of the members of the party who skied the slab that slid only moments later.
Donning avalanche safety gear, he said his crew went up aiming to ski a line a handful of acquaintances had skied the day before. Before descending, he said his group watched as two other skiers dropped down the Headlwall area with no trouble. Then, it was their turn, he said. When West and his partner reached the bottom, they turned around in time to see the avalanche coming toward them.
“Two of us were at the base, we took off running in the opposite direction,” he said.
All on the mountain that day were safe and no doubt lucky.
The avalanche was substantial, Mattice said. Experts are attributing the slide to a region-wide weak layer of snow about three to seven feet deep, created during a dry period in January and February.
Snow from Ketchikan to Whitehorse appears to be suffering from the same weak layer, Mattice said.
“This particular weak layer could be with us for quite some time,” he said.
He compared the layer of snow to a mousetrap with a stiff trigger, depressed by new snow. For the rest of the season, snow and wind could cause worrisome conditions, he said.
Other areas of Douglas Island have reported avalanches, as well. West said he’s heard of slides on both mount Troy and Jumbo.
“It’s a spooky condition when we get deep layers that are harder to predict,” Mattice said. “It’s an even spookier condition when (avalanches are) not only getting triggered remotely … (but) they can also be catastrophic in nature.”
In some places, due to terrain and condition variability, the weak layer doesn’t exist or isn’t as prominent, he said.
“The bottom line is if you’re not digging holes and making your own stability assessments, you’re guessing with your life and your safety,” he said. “And not just your life and your safety, but also the person who has to come rescue you, too.”
West had a bit of simple advice for backcountry enthusiasts.
“It’s just not really safe out there,” he said. “I’m not any expert. All I can say is be careful.”
• Contact Outdoors reporter Mary Catharine Martin at firstname.lastname@example.org. Abby Lowell contributed to this report.