Unreactive PS and weak surfaces BTL

CB Avalanche Center 2016-17 Observations

Location: Crested Butte Area
Date of Observation: 03/05/2017
Name: Zach Guy
Subject: Unreactive PS and weak surfaces BTL
Aspect: North, North East, East
Elevation: 9,000-11,100 ft.

Avalanches: None
Weather: Overcast skies, S-1 at 4 p.m. Calm winds in sheltered areas where we traveled, but snow transport observed on some high peaks from strong SW winds.
Snowpack: Traveled on numerous north through east facing slopes below treeline on Mt. Axtell and Mt. Emmons with no signs of instability and found unreactive persistent slab issues in several pits (See photos). Buried facet or facet/crust layers are generally 35-40 cm deep, ~1mm in size and rounding. Slabs are F to 4F and decomposing. Surfaces are generally 0.5mm near surface facets, transitioning to thin melt freeze crusts around 80* (ENE). Isolated pockets of preserved surface hoar, up to 15mm in size on E and N aspects.

NE aspect, 9,600 ft. Happy Chutes. 2 crust/facet layers ~35 cm deep. ECTN 22, BRK on facets below the bottom crust.

NE aspect, 10,600 ft. Mt. Axtell. ECTN 26, BRK on rounding facets 45 cm deep.

East aspect, 11,000 ft. Mt Axtell. Multiple crust facet layers 35 to 60 cm deep. ECTN 24 BRK on 1mm facets above the top-most crust.

Isolated pockets of large, surface hoar still in tact on E and N aspects, in some places above a crust. Most surfaces were small grained, near surface facets or wind-broken rounds.

North aspect, 10,000 ft on Mt. Axtell. ECTX. 1mm rounding facets buried 35 cm deep. Rain crust over rounding facets buried 65 cm deep.