Variable surface conditions in the Mammoth Area

SNOWPACK OBSERVATION
Mammoth Mountain Side country
Submission Info
Forecaster
Tuesday, January 7, 2020 - 2:00pm
37° 37' 50.79" N, 119° 2' 8.5776" W
Snowpit Observations
More detailed information about the snowpack: 

I took advantage of the lifts at Mammoth Mountain this morning to gain quick access to high elevations and multiple aspects.  My goal for today was to get an idea on how the surface conditions vary depending on elevation and aspect.  The winds were strong out of the Southwest today and seemed to increase throughout the day. Small amounts of blowing snow were observed at mid and upper elevations but I did not find any concerning wind deposit. I did see some surface cracking on thin wind board at 9700’ on an NW aspect.  At this location outside of the ski area boundary, the wind board was 1F hard, about 2” thick and was breaking under my feet into dinner plate size chunks. I dug a snow pit near this location and identified Near surface facets immediately below this wind crust.  While I was able to find the rain crust from earlier in December, it was very thin at this location. It has also been heavily decomposed and almost indiscernible from the layers immediately above and below. Tests in this location did not identify any layers of concern. Further down from the ridge on a more shaded and protected NNW aspect, surface faceting has kept the upper snowpack soft and loose.  Though in areas with significant sun exposure, a thin melt-freeze crust was grabby enough to keep me on my toes. 

After returning to the resort I ventured back to the top to get a look at the southern aspects. leaving the boundary near a feature known as Dave’s wave I found surface conditions to be quite firm. P+ wind board, large sastrugi and thin coverage dominate much of the upper mountain. Kicking through the wind board on an SW aspect at about 10900’ I found ~15cm~ of p+ wind board sitting on top of 4F faceted snow. Below 10,700’ or so the wind board thins, becomes breakable and eventually, the surface snow is dominated instead by a substantial melt-freeze crust. At upper elevations, I observed this crust to be about 1.5” thick but fairly crumbly. As I descended the S aspect, this crust gradually thinned, and elevations below 9500’ surface conditions were pretty soft.  At 2 pm at 9200’ on an S aspect with full sun exposure, the boot penetration was 20 cm, the surface temperature was .4° C, and the upper snowpack was damp.   Jumping around on steep rollovers and areas near rock outcroppings I was unable to initiate any surface sloughs or rollerballs. I suspect the last few days of sun has cooked down the surface snow substantially. 

No signs of instability were noted on my tour today, rather many signs of stability were observed. Wind and melt-freeze crusts of varying thickness seem to dominate nearly every aspect, with challenging ski conditions nearly everywhere I traveled today. All in all, it was a beautiful day in the mountains but let's keep the fingers crossed for a refresh in the near future

Snowpit or crown profile photo or graph: 
Snowpack photos: 
Weather Observations
Blowing Snow: 
Yes
Cloud Cover: 
Clear
Air temperature: 
Above Freezing
Wind Speed: 
Strong
Precipitation: 
None
Air temperature trend: 
Warming
Wind Direction: 
Southwest
Accumulation rate: 
None
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