As predicted, the weak mountain snowpack unloaded on a snowmobiler high marking on Crown Butte near Cooke City two days after Christmas. Luckily, the rider wasn't injured. But the size of the fracture was impressive.
According to the Gallatin National Forest Avalanche Center, the slide broke 2 to 4 feet deep and was 400 feet wide. The rider was near the top of the slide when it released and was caught in the avalanche but not buried. Smartly, his partner was watching a safe distance below.
The snow in that area contained a hard slab surface that was allowing riders easy traction on the way up. There were about 10 to 20 other tracks on the slope before it released, which emphasizes the somewhat fickle nature of such things.
As the Avalanche Center's Doug Chabot said in the daily forecast, "The take home point: Tracks do not equal stability."