Persistent Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Possible
- Size
- 1–2.5
Our 11 day storm track (1/31-2/10) blessed us with over 60 inches of new snow in the mountains, creating a persistent slab. The latter half of January was dry and gave us a layer of facets and buried surface hoar that is now buried under 3-4 feet of snow. This weak layer produced natural and human triggered avalanches from Saturday 2/1-Tuesday 2/4. It has been since February 4th when we have last had a report of people triggering avalanches on this layer. The snow above is now 3- 4 feetdeep of pencil to 1 finger hard snow for more than half of it. We are still getting full propigation on this layer in our test pits: PST 27/113 END.
While triggering this layer is becoming hard, it is still possible where the weak layer and slab has not slid. Riders on machines are more likely to trigger this weak layer and it would likely be a thin spot in the slab, near a rock or tree where the snow is also weaker.
(2/10/2025) Photo: George Halcom