Persistent Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Possible
- Size
- 1–2
Weak snow that formed in early December sits 2-4 feet below the surface and remains a lingering threat today. Triggering an avalanche at this depth carries severe consequences. While it is becoming more difficult to trigger these deeper layers, it cannot be ruled out. Avalanches at this depth have been observed as recently as 5 days ago. Thin spots in the slab are the most likely spots to impact these layers.
Large triggers in the form of groups, snowmobiles, avalanches within the new snow and falling cornices will increase the odds of impacting these layers. Use safe travel practices in order to minimize your exposure to this problem. Travel one at a time across steep terrain, use islands of safety when stopped and communicate with your group members throughout the day.
(1/9/2025)
Natural persistent slab avalanche that likely failed 1/7 on weak layers formed early season on the ground. Slab depths ranged from 2-3'
Photo: Alex Drinkard