Storm Slab Tests, Touchy Wind Slabs: Chicken Wing

Submission Info
Friday, March 23, 2018 - 1:00pm
Red Flags: 
Recent avalanche activity
Whumphing noises, shooting cracks, or collapsing
Recent loading by new snow, wind, or rain
37° 45' 18" N, 119° 2' 12.84" W
Snowpit Observations
More detailed information about the snowpack: 

Toured up well anchored, low angled terrain on the Chicken Wing to test lingering storm slabs and fresh wind slabs.

Kick tests along the top of the ridge were productive. Many small results and shooting cracks in 4F hard wind slabs on E and NE facing slopes. The largest result, D1, was triggered about 20' downslope and to the skier's R of the cornice I was stomping on (see video of cornice stomping and photo of remotely triggered D1). Kick turns had small shooting cracks up to 1m along the NE ridge above about 9200'. Hand shears failed with easy force under F+ hard deposits of wind broken snow 5-15cm thick on the approach to the summit. Ski cut on a small steep N facing test slope at 9600' had no results; the wind slab on this slope was harder, 1F+.

Test slopes to get a feel for the storm slabs at 8500' had no results. Sank through a 4F slab into softer snow below up to my knees or waist though. With no direct signs of instability I stopped to do some snowpack tests on a NNW slopes at 8900' to test the storm slab bonding. Snow depth=181cm, storm snow=85-100cm, ski pen=20cm, boot pen=75cm. CTM SP x2 down 40cm under 4F hard decomposing and fragmented grains on F hard preserved stellars; ECTP 14 x2 at the same interface. Several other small column tests were either resistant or were not repeatable. Storm snow structure was about 15cm of F hard snow from last night, over 25cm of 4F snow, over 30cm of F hard snow (easy to fall through, like post-holing on skis), over 15cm of 1F hard snow. Thin layer of moist facets above the moist 1F hard melt-freeze crust that was covered over by the start of the storm on 0320.

Snow below about 8600' was getting wet in the warm temperatures on the way down by 145p. No rollerballs observed, just sticky melt forms.

Windy day with consistent moderate Southerly winds with strong gusts transporting a lot of snow. Visible all day long across the range and on the drive back. See photo of blowing snow N of the June area.

Snowpack photos: 
Plenty of blowing snow north of June
D1 wind slab triggered from 20 upslope
Snowpit videos (tests, etc): 
Weather Observations
Blowing Snow: 
Cloud Cover: 
Air temperature: 
Above Freezing
Wind Speed: 
Air temperature trend: 
Wind Direction: 
Accumulation rate: 
More detailed information about the weather: 
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