This Ski Resort Just Recorded One of the Largest In-Bounds Avalanches in Its History

Mother Nature has provided another reminder that avalanches can occur on either side of a ski resort’s boundary.

Earlier this week, patrollers at Colorado’s Steamboat Resort published images and video of a massive avalanche that swept down four closed runs on the morning of Wednesday, November 27. Nobody was injured in the slide, which occurred near the summit of 10,570-foot Mount Werner.

“This is the largest slab avalanche we’ve seen at Steamboat in almost two decades,” patroller Matt Hartsel said in the video.

The slide swept down four advanced and expert runs that start at the top of the Morningside chairlift: Crowtrack, The Ridge, Chute 1, and Chute 2. It occurred after an early-season storm dumped two feet of new powder on the resort in just two days. Nobody saw the actual avalanche.

According to a field report that Hartsel submitted to the Colorado Avalanche Information Center, the crown of the avalanche was nearly 1,000 feet long, and the slide swept down the steep runs and came to rest on flatter terrain. Hartsel wrote that it broke free from a a weak “faceted” layer of snow that fell early in the season. In his report, Harsel said that patrol detonated explosives on Mount Werner on Monday, December 2, but the charges did not produce an additional slide.

“No known witnesses, believed to be natural trigger,” he wrote.

Steamboat’s ski patrol urged visitors to respect trail closures—had skiers ducked the ropes to descend or climb the terrain during the storm, they could have been injured or killed. “There are areas of our mountain that are not ready to be opened,” patroller Riley Wilkinson said in the video. “Not respecting closures places you and patrollers in danger.”

Steamboat’s ski patrol has not announced when the area impacted by the avalanche, which is commonly called “Christmas Tree Bowl,” will open for the general public. Loryn Duke, a resort spokesperson, said that it’s often the last terrain on the mountain to open, and sometimes the ropes don’t drop until after Christmas.

“Our patrol teams do avalanche mitigation pre-opening, including hand bombs and ski cutting, to stabilize the snow as much as humanly possible prior to opening and then do daily mitigation as necessary,” Duke told Outside in an email.

“This type of slide is Mother Nature doing natural mitigation on the slope,” Duke added. “The weak layer has sluffed off and compacted below the slide area. Now we will continue to monitor new snow and determine when the snow is stable enough for skiers and riders to enjoy.”

The slide is another reminder of the avalanche danger that exists during the early season, as the repeated cycle of storms and sunshine create unstable layers in the snowpack, even on runs that lay within a resort’s boundaries. The Steamboat slide occurred just four days after the resort opened to the general public on November 23—currently only 36 percent of the trails are open.

But deadly conditions can exist on in-bounds terrain later in the season, even after ski patrollers have conducted avalanche mitigation on trails. Patrollers will trigger slides with explosives, or by slope-cutting—skiing at a 45-degree angle across a hillside—prior to a run opening to reduce the risk of uncontrolled avalanches while the terrain is open. On January 10, 2024, a deadly avalanche rumbled down experts-only runs at California’s Palisades Tahoe shortly after patrollers opened the terrain for the season. The slide killed one visitor and buried others.

Avalanche expert Paul Baugher, who ran the ski patrol at Washington’s Crystal Mountain Resort from 1987 until 2016, told Outside that he’s seen glaring similarities between deadly avalanches that have occurred within the boundaries of U.S. ski resorts. Baugher co-authored a 2023 report titled Characteristics of Inbounds Avalanche Fatalities at United States Ski Areas that studied 14 deadly in-bounds slides between 2003 and 2023.

“They happened early in the season, and the worst-case scenario was when they occurred on only a marginally unstable slope,” Baugher said. “If you have a fully unstable slope, ski patrol can do mitigation action and get results because the sensitivity to trigger an avalanche is high. But if you have a marginally unstable slope, you may not be able to get it to slide, and the snow just builds up.”

Baugher told Outside that skiers should always exercise caution when skiing expert terrain early in the season—specifically in the days after the runs have opened to the public. He recommends always skiing with a friend, and bringing personal avalanche safety gear: a beacon, shovel, and probe, and the knowledge to use them.

“If you think danger has been engineered out of skiing at a resort, you’re wrong,” he said.