Large D3 Avalanche Rips Through Avalanche Gulch on Mount Shasta

A large avalanche was confirmed in Avalanche Gulch on Mount Shasta following last week’s powerful winter storm, showing the dangerous backcountry conditions that persist across the region.

According to a report from the Mount Shasta Avalanche Center, forecasters documented a natural D3 wind slab avalanche on Green Butte Ridge that funneled into Avalanche Gulch. The slide likely occurred on December 26 during the height of storm instability and was observed during a site visit on December 28.

In avalanche classification, a D3 slide is considered “large” — powerful enough to bury or destroy a car, damage structures, or severely injure or kill a person. Forecasters believe the avalanche was triggered when a smaller D2 wind slab higher on the slope failed, causing the larger slab below to release. The failure likely occurred on a weak layer or density change within the new snow and may have stepped down into deeper layers of the snowpack.

The crown was several feet deep in places and stretched an estimated 1,000 feet wide, forming in nearly the same location as a major avalanche that occurred during Presidents’ Day weekend in 2024.

Avalanche Gulch is one of the most popular climbing and skiing routes on Mount Shasta, making the slide a stark reminder that even familiar terrain can become extremely hazardous after major storms. Forecasters continue to urge backcountry users to avoid avalanche terrain and check daily avalanche forecasts before heading out.