Small wind slabs and large collapses

CB Avalanche Center2016-17 Observations

Location: Kebler Pass Area
Date of Observation: 01/27/2017
Name: Zach Guy and Billy Rankin
Subject: Small wind slabs and large collapses
Aspect: South East
Elevation: 11,500

Avalanches: Several small (D1) windslabs above treeline that ran in the past 24 to 48 hours or so, on NE, E, and S aspects in the Ruby Range. One ran today. Evidence of some larger debris piles from earlier in the storm cycle from above treeline paths, but crowns are blown clean now. Explosive triggered one large persistent slab on a SE aspect near treeline, 65-80 cm thick. HS-AB-R2-D2-O on facets and decomposing SH over a crust (Jan 19 interface). Remotely ski triggered small pocket on SE aspect near treeline. HS-ASr-R1-D1-I. 40-50cm deep, 20′ wide on the Jan 19 interface. ¬†Good views of from Scarp Ridge with no other significant slides observed.
Weather: Moderate plumes from northerly winds this morning eased through the day. Cold temps, few clouds.
Snowpack: In Irwin Terrain, skier triggered multiple large collapses and a long shooting crack on a S/SE aspect near treeline, ~33* slope, that didn’t avalanche. Subsequent test pits revealed the Jan 19 interface 50cm’s down and produced a couple CTV during isolation, CTE 5, ECTP1 & 12 & 15 all Sudden Collapses on the crust with 1-2mm facets and some SH observed.

Recent wind slab

Explosive triggered persistent slab. HS-AB-R2-D2-O

D1 wind slab ran today. Maybe cornice triggered?

Small, recent wind slabs

Larger debris from last avalanche cycle. Crown filled in.

Crown of explosive triggered persistent slab, 60-85 cm thick on facet/SH/crust. SE aspect NTL