Unstable Snowpack Test Results on Castle Peak

Location Name: 
North Side Castle Peak
Donner Summit Area
Date and time of observation: 
Tue, 11/22/2016 - 12:00
Location Map: 
United States
39° 21' 46.7244" N, 120° 20' 31.7652" W

Red Flags: 
Recent loading by new snow, wind, or rain

Observation made by: Forecaster
Snowpit Observations
More detailed information about the snowpack: 

1-2' of recent storm snow in the Castle Peak area.  On North aspects above 8300', this new storm snow sits on top of old existing snow from October and early November.  The existing snow is made up of firm crusts and weak faceted snow that formed in early November.  All snowpack test results indicated instability pointing towards a potential persistant weak layer/persistant slab problem.  Numerous snowpack tests showed repeatable weakness and failure below the 11/16 rain crust in faceted old snow.  This layer is present in these areas above 8300' on North aspects.  These areas are also where the most snow exists for recreation with total snow depths at 3-4'.

Photo#1:  North side of Castle Peak.  Several large loose dry avalanches, sluffing, in steeper terrain.

Photo#2:  Active wind loading throughout the day.  Moderate SW winds moving snow and building wind slabs.

Photo#3:  Surface hoar 4-6mm in size throughout area.  In wind exposed areas, SH seen blown over or not present.  In many other areas including solar aspects SH was present into mid afternoon hours.

Snowpit or crown profile photo or graph: 
Snowpack photos: 
Snowpit videos (tests, etc): 

CastlePeak2016 11 22

Weather Observations
Blowing Snow: 
Cloud Cover: 
50% of the sky covered by clouds
Air temperature: 
Below Freezing
Wind Speed: 
Air temperature trend: 
Wind Direction: 
More detailed information about the weather: 

Winds and high clouds increasing throughout the day.