Persistent Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Possible
- Size
- 1–2
It has been four days since a human-triggered avalanche was reported (Avalanche); however, skiers and riders continue to report widespread collapsing across the forecast area. This is enough to keep this problem on the list, and triggering a slide 2-3.5 feet thick remains possible.
- Avalanches will be more likely on slopes steeper than about 30 degrees.
- Whumphing and collapsing of the snowpack are indications that there is weak snow failing near the ground.
- You may be able to trigger slides in gullies, alpine bowls, or on convex rolls where December's wind formed smooth, firm slabs over weak snow below (Photo).
- As last week's storm snow settles and stiffens, triggering a slide where recent snow fell on weak snow near the ground isn't out of the question (Photo).
Before committing to steep slopes, take the time to dig down and assess for these weak layers. You can decrease your risk by riding slopes one at a time and choosing slopes free of exposed rocks, cliffs, or gullies.
Photo: Hatcher Pass Avalanche Center