Avalanche
- Slab Width
- 15 m
- Weak Layer
- Facets
- Trigger Type
- Skier
- Vertical Fall
- 61 m
- Avalanche Type
- Soft Slab
- Slab Thickness
- 30 cm
- Trigger Detail
- Remotely Triggered
- Start Zone Aspect
- North
- Avalanche Problem
- Persistent Weak Layer
- Start Zone Elevation
- 2865 m
Traveled through BCC, Millcreek and the PC ridgleline today to look at the state of the area's mid-snowpack facet layers. Since November the PC ridgeline has held the most developed & weakest facets I've observed in the central Wasatch and today reconfirmed this. With continuous localized collapses throughout the day, walking the eastern shoulder of Little Water Peak remotely triggered a slide down to the pre-December 11 interface.
The layer of concern in recent activity formed when late Nov. storms laid small quantities of snow on top of a thermal crust from ~Nov. 19 warming. This crust and high pressure promoted faceting until Dec. 11 snow capped the weakness with one of two layers that make up our current slab. 1-2 mm facets lie mid-snowpack and exist both above and below the crust (which in many places has deteriorated substantially) but the upper layer has been the failure layer for all slab avalanches I have seen since Dec. 11.
Test in a NW-facing HS 65 snowpit showed this layer 32 cm down. Knowing the weak layer is present and slab on top formed, we tested the propagation propensity and slab cohesiveness.
Robby Young, a local snow safety specialist and educator, shared his intimate knowledge of the area's snow history and activity. Here, after a (sudden planar) ECTP14, he shows propagation with a SLECT (Stupidly Long ECT). This 180 cm wide column fully propagated on tap 13 (SLECTP13).
In the video Robby shows our PST 20/120 (End) down 32 cm. The slab is here and the weakness quite uniform from NW through E aspects in this area.