Problematic surfaces

CB Avalanche Center 2016-17 Observations

Location: Crested Butte Area
Date of Observation: 01/01/2017
Name: Zach Guy and Evan Ross
Subject: Problematic surfaces
Aspect: North East, East
Elevation: 9,000-12,200 ft

Avalanches: No signs of instability. No recent activity.
Weather: S-1 to S1 throughout the day. Overcast skies. Light winds with minimal transport.
Snowpack: ~2″ of new, low-density snow.
On NE and E aspects near treeline, the storm interface is smooth windboard, and the new snow was not bonding well to this surface. Lots of shallow, harmless sluffing. Dug one pit on a wind loaded NE aspect. About 120cm of 1F+ slab over 4F+ 1.5mm rounding facets. No results in ECTs or with additional loading steps on deep tap ECTs. The surface (below the new snow) was 1cm, 1F wind crust over small grained facets. The starting zones that we traveled near had variable snow depths due to previous avalanches and wind affects.

Below treeline, the storm interface is fist hard near surface facets, ~1mm, and several hand pits showed multiple facet layers in the upper 25 cm of the snowpack; not problematic until a slab arrives. Snow depth was generally about 70 to 90 cm deep, with a few shallower and faceted/unsupportive areas on steep rollovers.