Persistent Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Unlikely
- Size
- 1.5–2.5
The potential to trigger an avalanche in the crust-facet layering from late January remains. Most avalanches were reported in the West North Zone, however a similar snow structure is present in the West Central Zone. Ten days have passed since a human triggered avalanche, but reports of natural avalanches continue to slowly trickle in. Here is what we know:
- The layers are most prevalent on shady aspects above 5400 feet in elevation.
- There is around 2 feet of new snow above the weak layer.
- Observed avalanche sizes are ~D2.
- Snowpack tests produce inconsistent results, sometimes even in the same snowpit.
- Many steep slopes where riders got out on with no results saw nearby slopes or another location on that slope avalanche on the weak layer.
Although the likelihood of triggering one of these avalanches is low, the consequences could be high if you are in a bad spot in the terrain. Remember, persistent slab avalanches can be triggered from low on the slope or remotely and factor in the consequences of triggering a large avalanche on the slope in question.
(2/12/2022)
A natural avalanche suspected of failing in January 30th crust-facet layers. Estimated date of occurrence was around a week ago.
Photo: Graham Clark