Wet snow on Andesite

Location Name: 
Andesite Ridge
Region: 
Donner Summit Area
Date and time of observation: 
Fri, 01/29/2016 - 11:00
Location Map: 
United States
39° 20' 35.7036" N, 120° 21' 9.4608" W
See map: Google Maps
US


Red Flags: 
Recent loading by new snow, wind, or rain
Obvious avalanche path
Observation made by: Forecaster
Snowpit Observations
More detailed information about the snowpack: 

Moderate to heavy rain on Donner Summit during the late morning hours today. Snow level was well above our high point of travel at 7,500'. Most likely up around 9,000'-9,500'. Wet surface snow was 15 to 30 cm deep at mid day and getting deeper. Widespread human triggered roller balls starting at 10 cm in diameter increasing to 1.2 m as they gained more snow and size while rolling downhill. Skier triggered loose wet avalanches were easy to trigger on very steep test slopes. Isolated minor skier triggered cracking was observed.

Photo 1: Intentionally skier triggered loose wet avalanche failing 15-25 cm deep.

Photo 2: Skier triggered roller balls and pinwheels, very typical of conditions out there late morning.

Photo 3: Very large skier triggered roller ball 1.2 m in diameter.

Photo 4: Minor skier triggered cracking 45 cm long, 20 cm deep.

Snowpack photos: 
Weather Observations
Blowing Snow: 
No
Cloud Cover: 
100% of the sky covered by clouds
Air temperature: 
Above Freezing
Wind Speed: 
Moderate
Precipitation: 
Rain
Air temperature trend: 
Warming
Wind Direction: 
Southwest
Accumulation rate: 
More detailed information about the weather: