Persistent Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Possible
- Size
- 2
This zone has persistent weak layers buried 1-3 feet deep on most middle and upper elevation slopes. People often ask how these weak layers heal. There's no magical formula, but the most important factor is time. It's been a week or more since the snowpack has been significantly stressed by new snow, wind, or warming temperatures. Imagine how you'd feel after a week on the beach with no email, no texts, and no news. Given a week of relaxation, both you and the snowpack will feel better—but that doesn't mean your problems have miraculously disappeared forever.
As the likelihood of triggering an avalanche continues to decrease, it's important to understand where the chances remain the greatest. You can reduce most of the risk of triggering a slide by avoiding terrain with these characteristics:
- Wind-loaded terrain: Slopes where recent or past wind formed drifts and/or stiffened the snow surface.
- Steeper slopes: "Prime-time" avalanche terrain around 35-45 degrees in steepness.
- Southerly facing terrain: Crusts and facets 2-3 feet deep seem to be stabilizing more slowly on SW-S-SE aspects than the weak layers on shadier slopes.
ADDITIONAL DISCUSSIONIn some upper elevation locations, yesterday's 1-2 inches of new snow was getting transported by gusty W to NW winds (see video). You may find thin, sensitive wind slabs (like these) today along higher ridgelines.