Ruby Range Obs

Location: Kebler Pass Area
Date of Observation: 01/26/2016
Name: Zach Guy
Subject: Ruby Range Obs
Aspect: North East, East, South East
Elevation: 10,800-12,800 ft

Avalanches: Several natural D2 soft slabs that likely failed on or before 1/21/16 on SE and S aspects above treeline. (Galena Peak, Richmond Peak, and the ridge between Mt. Justice and Purple Mountain). One faint crown, D1.5, on a West aspect ATL on Garfield Peak.
Took quick look at the crown of the SS-N-R2-D2.5-O crown on the S/SE face of Purple that was first observed 1/21/16. The crown was roughly 70 to 120 cm deep. It appeared to fail on 4F-, 1mm facets below the Jan 14th crust, which was 4 cm thick, 1F. There were no noticeable facets above the crust at my pit location, just 1F rounds.
Weather: Clear, calm winds, cold in the shade, warm in the sun.
Snowpack: ~10″ of storm snow, largely unaffected by winds. Isolated soft drifts up to 18″ deep and some isolated cracking in the top few inches of snow. No other signs of storm instability except very small sluffs in steep terrain.
On a 30 degree ENE aspect at 12,000 ft: Total snow depth was 220 cm. The Jan 14th facet layer is 80 cm deep, 4F hard, 0.5mm in size and rounding. The slab above it is 1F hard at this interface, .3mm rounds. No propagating results in ECTs or PSTs. DT 22, Q2, SC.
On SE aspects N/ATL, the Jan 24th melt-freeze crust is ~2cm thick, supporting skis but boot pen easily breaks through. A thin new crust formed today on steep S/SE slopes.

Older crown lines visible looking north towards Snowmass Peak.  Crowns on Richmond (foreground), Galena, and Justice Ridge.  S and SE aspects ATL. Probably failed 1/20 or 1/21.

Older crown lines visible looking north towards Snowmass Peak. Crowns on Richmond (foreground), Galena, and Justice Ridge. S and SE aspects ATL. Probably failed 1/20 or 1/21.

Explosive triggered slides today at Irwin. SW and W aspects in Robinson Basin.

Explosive triggered slides today at Irwin. SW and W aspects in Robinson Basin.

IMG_5630-001

Old crown on Purple Peak, S/SE aspect above treeline. The slide appeared to break below the January 14th meltfreeze crust on 4F-, 1mm facets, about a meter deep on average. Likely failed 1/20 or 1/21.

IMG_5634-001