Persistent Slabs
- Alta quota
- Limite del bosco
- Sotto il limite del bosco
- Probabilità
- Possible
- Dimensione
- 2
I just don't trust this structure. Our Dry January Layer (DJL) of faceted snow is now buried up to two feet deep and is the weak layer for four avalanche fatalities and more than 60 reported avalanches. The slab on top of the DJL has gained strength, and signs of instability - such as collapsing - are no longer common. But an avalanche failing on this layer will be up to two feet deep, and possibly hundreds of feet wide. Spatial variability, rain and temperature crusts, rain on snow, and warm temperatures complicate things:
- At upper elevations, you are more likely to trigger an avalanche where the snowpack is thinner.
- At mid elevations, warm temperatures and rain on snow has further weakened the DJL, and wet slabs failing on moist, weak grains at our DJL are possible, especially around any of the many rain crusts that are present in the snowpack.
Natural avalanche on the Ben Lomond headwall from Wednesday, 2/26. Likely a wet slab avalanche failing on facets around a crust. [Photo: Cage Vigil]