‘Persistent weak layer’ caused fatal Pole Canyon avalanche

SALT LAKE CITY — An avalanche last week in Pole Canyon, near Cedar Fort, was accidentally triggered by a snowmobiler, along with a persistent weak layer of snow.

In its report released this week on the fatal avalanche, the Utah Avalanche Center described a persistent weak layer of snow as one that did not receive enough sunshine in-between snow storms.

“We’ve had just brief moments of sunshine,” said Mark Staples with the Utah Avalanche Center, in a YouTube video. “So (the snow) hasn’t been cooked, it gets just enough sunshine to warm it up and create a crust. 

“What it also does … it creates a thin, weak layer near that crust.”

The avalanche was described as “massive,” more than 4,200 feet wide. It traveled around 2,360 vertical feet downhill.

“When you combine that with these big storms we’ve been getting, I mean every storm we’ve gotten is inches of water and feet of snow,” said Mark Staples with the Utah Avalanche Center, “that overloads these weak layers.”

Despite having a beacon and airbag, Brett Warner of Highland, Utah was killed. He was buried in 13 feet of snow.

Hear our interview on Utah’s Morning News with Mark Staples, below.