Persistent Slabs
- Alta quota
- Limite del bosco
- Sotto il limite del bosco
- Probabilità
- Likely
- Dimensione
- 3
Persistent weak layers of faceted snow continue to plague the bottom part of the snowpack. What has changed is the slab on top. Recent snowfall, recent wind and recent warm temperatures have created a dense slab on top that will avalanche. Imagine a building with a weak foundation but we keep adding additional floors on top - eventually the whole structure will collapse.
The result of this dense slab is that avalanches are getting bigger both in depth and area. Expect avalanches that can be hundreds of feet wide and 2-3 feet deep.
- Above and near treeline this avalanche problem is widespread.
- Below treeline, the weak layer is widespread but the distribution of the slab on top is more pockety and a little dependent on where winds drifted snow and helped create a more cohesive slab.
What's tricky is that as the slab on top of the persistent weak layers becomes thicker and denser, avalanches get a little bit harder to trigger. This means the first person to ride on or even near a slope may not trigger it. Instead, it may be the 2nd, 3rd, or even 10th person on a slope who triggers it. Seeing tracks on slope doesn't mean it's safe.
In the video below, Craig describes an avalanche that partially buried 4 riders on Sunday. Luckily they were all ok.
