Large slab avalanche and weak layers

CB Avalanche Center2018-19 Observations

Location: Kebler Pass Area
Date of Observation: 01/05/2019
Name: Zach Kinler

Subject: Large slab avalanche and weak layers
Aspect: North, North East, East
Elevation: 10,000′-10,600′


See picture below of suspected snowmobile triggered D2 slab avalanche from this morning. The avalanche was in part of the path of a larger natural slide that occurred on 12/5. The crown appeared 3-4 ft deep from a distance and ran ~250-300ft. It broke in old snow.

Weather: Increasing clouds with high ~0C, moderate WSW winds on a quick trip up to Scarps Ridge. Light and variable winds below ridge top.

Snowpack: Punched a couple holes on an East and North aspect below tree line to test our mid December weak layers before our next loading. These Surface Hoar and Faceted Crystal layers are clearly visible while excavating the pit and produced fractures in long column tests with no propagation within the standard test. Additional loading steps and prying of the slab produced planar fractures in all tests. The overlying slabs are still very soft at F- 4F- which may be limiting propagation at this point. See pictures below with a few test results.

Surface conditions were 5 mm SH laying flat on East and 10 mm upright SH on North which look to get buried tomorrow.