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Green Butte Ridge, General Observations, CT2 / ECTP1
Location Name:
West Aspect, Green Butte Ridge, TreelineRegion:
Mt. ShastaDate and time of observation:
Wed, 12/14/2016 - 11:56pmObservation made by:
Professional ObserverRed Flags:
Recent loading by new snow, wind, or rain
Location Map
United States
41° 22' 2.388" N, 122° 13' 22.512" W
See map: Google Maps
US
Snowpack Observations
Details
Photos
Weather Observations
Details
From 1:30 p.m. to 5 p.m., Bunny Flat was obscured, with less than 100' of visibility, and experencing a mix of sleet and rain.
If you like making snow men and throwing snowballs, you will have great snow for it up to 7700'. Interpret this as wet snow conditions.
Lower Green Butte Ridge shows evidence of windloading on both westerly and easterly aspects with around 38 cm (15 in) of new snow 1/3 of the way down each side. The lower ridge line has a new snow depth of around 21 cm.
Above 7700', a 1 cm, pencil-hard melt freeze crust has formed. At 4:30 p.m., skiing from treeline to 7700' feet was dust on breakable crust, then turning to heavy wet snow to the parking lot.
Statistics
Cloud Cover:
100% of the sky covered by cloudsBlowing Snow:
YesPrecipitation:
SnowAccumulation rate:
Less than 1 in. per hourAir temperature:
Below FreezingAir temperature trend:
StaticWind Speed:
LightWind Direction:
East
A test pit was dug on the west facing (275 degrees) slope of upper green butte ridge, on the edge of treeline, exposed to wind loading effects. Slope was 29 degrees at an elevation of 8061'. Temperature was -3 degrees C.
Test Results: CT2, Q1; ECTP1, Q1
Failures occured at about 36 cm (14.17 in) below the snowpack surface, on a density change (4F - F) in new storm snow on top of an ice / melt-freeze crust. Layer collapsed without sliding, but slid with full propagation with slight force. Subsequent tests below 36 cm yielded no failures.
No whumphing or shooting cracks were observed from Bunny Flat to the test site. No failures observed with ski jumps on steep convexities and steep tree wells.
On lower Green Butte Ridge, below 7700', hand tests yielded easily triggered propagating failures of new wet snow on top of a .5-1cm. crust 21 cm (8.3 in) below the snowpack surface.