Location: Crested Butte Area
Date of Observation: 12/15/2018
Name: Steve Banks
Subject: Gothic Obs
Aspect: East, West
Elevation: 9,500->10,600
Avalanches:
No new avalanches observed. Some small WL dribblers steep SW slopes ATL
Weather: Mostly clear skies with warm temps and calm winds. Some high cloud passage from 11-12:30 accompanied by light westerly winds. High temp hit +2 C.
Snowpack: Morning surface hoar destroyed by sun but preserved and up to 4mm on shady slopes. SE-S-SW slopes BTL have a crust up to 3 cms thick. On these aspects we also found a thin, soft crust 6-10 cms below the surface with near crust facets above and below. This layer showed clean shears with shovel tilt tests.
Several large collapses BTL on West and East facing aspects between 9,600-10,000’ on low angle slopes. Some cracks went to the ground/basal facets. HS 55-70 cms.
On East aspects near 10,000’ snow pits revealed Persisten Slab structure with 4F to 1F slabs resting over 4F to F hard facets near the ground (14 cms of 3-4 mm facets) with ECTP 16 SP in a pit with HS of 78 cms. A pit in an adjacent slope got repeated ECTX scores with 100 cm snowpack. However on this location, prying on the column showed a very clean shear down 45 cms on the interface moving from 4F to 1F with small .5 mm facets.
In a nut shell: the persistent slab problem is there on shady slopes below treeline and is becoming difficult to trigger in some places, easier in others.
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