Persistent Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Likely
- Size
- 1.5–3
Weak snow from December is widespread and located 2-4 feet down at mid and upper elevations and 1-2 feet down at lower elevations. Avalanches have been triggered on all aspects and elevations and the possibility of remotely triggering a large hard slab avalanche continues to exist. Recent loading and warm temperatures have caused significant slab settlement. As we get further out from the last loading event and the snowpack begins to adjust, it will become harder to trigger avalanches but the consequence of a large avalanche remains high. Obvious warning signs might not be present until you trigger the avalanche and tracks on the slope might lure you in. Continue to maintain wide safety margins in the current conditions by choosing to ride lower angle terrain, using cautious route finding and safe travel techniques.
The low elevation hazard was reduced to moderate today. This does not mean that exiting the mountains is safer. The weak layers are present, and collapsing continues. This hazard rating reflects a slightly less sensistive snowpack, meaning it could be more difficutly to collapse a weak layer and trigger an avalanche. By definition during moderate danger, human triggered avalanches are possible and they can still be large. Continue to give steep low elevation slopes room, particularly deep shady aspects that hold older weak snow. Terrain traps and gullies remain suspect and keep an eye on pockets of avalanche terrain that could carry you through conseqential terrain.
(1/20/2024) A large, wide propagating persistent slab avalanche that occurred south of JHMR.