1-foot snowfall in 24 hours prompts avalanche warning in Montana's Cooke City, West Yellowstone, and Idaho's Island Park.

A backcountry avalanche warning has been issued for Montana's Cooke City, Lionhead area near West Yellowstone, and Idaho's Island Park. Over a foot of snow has fallen in the last 24 hours, creating extremely dangerous avalanche conditions. The Gallatin National Forest Avalanche Center warns that human-triggered and natural avalanches are likely, and advises avoiding avalanche terrain.