Persistent Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Very Likely
- Size
- 3
I hope by now everyone is fully aware of the dangers posed by our persistent weak layer problem. Poor snowpack structure exists at all elevations facing the north half of the compass. Last week's 22 inches of snow is now perched on top of a pre-existing snowpack that was faceted through to the ground. Near and above treeline, especially on slopes facing N-NE-E, hard slabs of wind drifted snow, 2-4 feet thick have formed over top of these weak layers and dangerous human triggered avalanches are likely. Most avalanches will initially fail on a layer of preserved near surface facets that were covered up on February 11 before stepping down deeper into the snowpack but this is all academic. Any triggered avalanche in these areas will be virtually unsurvivable. Below treeline, soft slabs up to 18 inches thick exist over top of weak, faceted snow. Although not as threatening as the larger, hard slab avalanches higher up, these shallower, soft slab avalanches are dangerous enough to ruin your day or more. Avoid slopes steeper than 30 degrees that face the north half of the compass.
