A Deep Slab Avalanche Cycle
A unique early season setup with low snowfall and cold temperatures in the mountains surrounding Valdez has produced several remarkable avalanche cycles this season, see the Valdez Avalanche Center website for more information and current conditions.
The lack of snowfall in the fall weakened snow at the surface through a process known as faceting. This occurs when snow grains are transformed into larger, angular grains, have weak bonds with neighbouring snow grains, and often are referred to as sugary snow.
As regular snowfall returned to the area, the weak snow at the base of the snowpack became buried deeper and deeper until the mountains produced various avalanche cycles on these deep persistent weak layers, some of which were exceptionally large.
Deep slab avalanche problems can linger and are particularly difficult to forecast and manage. The are very destructive and dangerous due to the large amount of snow involved. Tests and observations can be unreliable and their behavior is unpredictable. Read more.
*Image from the Valdez Avlanche Center 12/17-18 Forecast page under Avalanche Activity