By Emily Stifler Explorebigsky.com Managing Editor

BRIDGER BOWL – Bridger Bowl closed all but the Powder Park lift today due to heavy new snow that pushed a weak snowpack past the breaking point.

An early morning explosive test caused a major wet slab avalanche in Sluice Box, a gully next to the Bridger Chair. That slide ran full path all the way to the beginner run below, tearing out mature timber on its way.

“We pulled back our control program at that point and just went for some pockets to see if we could open our Alpine lift terrain,” said Pete Maleski, Bridger’s snow safety director.

Ensuing control work on the Ridge affected only new snow above North Bowl; however when a team dropped in elevation to Bridger Gully—where the snow was “really rotten and wet”—an explosive placement caused an even more destructive avalanche, Maleski said.

It started as a loose soft slab but after running downhill several hundred feet, it initiated a larger avalanche that tore Bridger Gully out wall-to-wall at least five feet deep, taking with it the entire season’s snowpack. Running approximately 1,800 feet, the avalanche left a debris pile 20 feet deep where it ended, almost adjacent to the level of the Alpine lift bottom terminal.

The ski area had been closed the previous day because of excessively warm temperatures and avalanche activity out of bounds.

The Bridgers have been in a major avalanche cycle since an event on Saddle Peak a month ago. Since then, dozens of sizable natural and human triggered avalanches have been recorded, including just outside the ski area boundaries.

Like the Bridger Gully avalanche, most of the backcountry avalanches initiated at mid-elevations, and slid on a layer of facets left from October snow.

Monday night’s storm left eight inches of new snow on the mountain, with 1.5 inches of snow water equivalent (SWE). The two nights prior had been without freezing temps, and the snowpack was saturated all the way through, Maleski said.

“Our best guess it that water percolated off the rocks and lubed up the weak layer below.”

The patrol saw similar results in Slushman’s Ravine and D Route, to the south.

Bridger’s mountain manager Randy Elliot told Maleski this is the farthest he’s ever seen Bridger Gully run.