Storm Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Likely
- Size
- 1–2
The most likely avalanche problem a person will encounter today is storm slab avalanches. The most dangerous avalanche problem will be triggering a persistent weak layer (see problem 2) in the mid elevation band.
Valdez received 4" of new snow in the last 24 hours as of 5:30 am with Thompson Pass likely on the lighter side. We can expect an additional 4-10 inches of snow today with the Maritime zone seeing the higher end of accumulation. The new snow is low density and will easily be redistributed by any wind that occurs. Expect instabilities at the surface as well as deeper down.
Except for a few short breaks in precipitation, snowfall has been fairly steady over the last 10 days. Storm slabs are building without time for the snowpack to adjust. Expect to find various density changes within the new snow that will be capable of producing avalanches in steep terrain. Areas where the wind has redistributed the new snow and stiffened the surface will be the most likely areas to trigger an avalanche.
Watch for signs of instability such as shooting cracks and collapsing. These are bullseye indicators that unstable snow exists and moving to terrain <30° is a good idea. Keeping terrain choices simple today and avoiding large avalanche paths is recommended.
Photo: NWS