Persistent Slabs
- Alpin
- Limite forestière
- Sous la limite forestière
- Probabilité
- Likely
- Taille
- 2
Old snow from November became very weak and faceted on west, north, and east facing slopes mostly near and above treeline. It may exist in pockets below treeline. This layer is easy to find and you can see it clearly in any snowpit. The recent storm provided great coverage and dense snow to help build a base, but it also created a slab of cohesive snow on top of this persistent weak layer.
This persistent weak layer (PWL) is here to stay for some time, and slab avalanches fracturing on this PWL remain likely.
Weak snow under the dense new snow can be seen in this photo of an extended column test that fractured after only three light taps from the wrist in Mill Hollow. (Photo - Katz/Nassetta)
Nikki shows the set up in this video. Walking anywhere on foot yesterday was extremely difficult as you would punch through the dense snow and sink to the ground. She laughed at me as I crawled back to the sled.