Targeted weak layers W of Donner Ridge

Location Name: 
Top Negro Canyon; W of Donner Ridge
Region: 
Donner Summit Area
Date and time of observation: 
Wed, 02/10/2016 - 11:01
Location Map: 
United States
39° 20' 48.8508" N, 120° 17' 55.8024" W
See map: Google Maps
US



Observation made by: Educator at Donner Summit Avalanche Seminars
Snowpit Observations
More detailed information about the snowpack: 

We targeted the weak(est) layers within the top 80 cm of the snowpack this morning on the N facing (015 degrees) terrain at top of Negro Canyon.  Large portions of this slope were wind-scoured but we parked ourselves mid-cirque where 15-20 cm of cold, soft snow existed on the surface.  HS ranged from 180 to 240 cm; Tsurf = -4.5 C, T20 = -2.5 C.  airT = 9 C.  Snow temps approached 0 C around 60 cm from surface.  Targeted layers were soft, fine NCFs .25 - .5 mm in size below (and in one case above) the 20160129 rain crust.  PST 95/100 end x2; PST 67/100 end; PST 27/100 SF; CTN x6; CTH Q2 x2.  Slope angle 22 - 24 degrees.  No signs of instability noted.  Upon returning to south-facing snow, light cloud cover and a light SW wind conspired to keep the snow surface a little cooler and harder making for a happy ski descent.

Snowpack photos: 
Weather Observations
Air temperature: 
Above Freezing
Wind Speed: 
Light
Air temperature trend: 
Warming
Wind Direction: 
Southwest