The Chugach Avalanche Information Center issued an advisory on Sunday that avalanche danger is high for the Turnagain Area both above and below the treeline. Both natural and human-triggered avalanches are “very likely,” and travel in avalanche terrain is not recommended.
The unusually warm weather system moving through Southcentral has brought rain at all elevations, which the center warns is destabilizing the snowpack and may potentially release huge, full-depth avalanches. These avalanches can run their course all the way to flatlands, and deposit lots of debris, making travel in lower areas dangerous, as well.
The primary concern is deep slab avalanches, where the bottom layers of the snowpack weaken and trigger the entire slab of snow to slide down the hillside. The last deep slab avalanche was four days ago, but today the likelihood will increase again.
The secondary concern is the rainfall on snow above 1,000 feet. The center writes:
As many old-timers say, "Rain on dry snow is never a good thing.” These wet avalanches can initiate in the top foot or two of the pack where the rain is being absorbed and become quite large on their descent by entraining additional snow in its path. They also have the ability to “step down” and trigger a deep slab avalanche, in which case will mostly likely be quite large. Wet snow avalanches contain very dense snow that is typically slow moving but they also mow down and destroy most things in their path.
Up-to-date avalanche information available at the center’s website.