Professional Observation

Observation Details

Signs of Unstable Snow

Snow Stability

Key Points

• I set out from the top of the June Mountain ski area today to see if there had been any wind slab development in the alpine and if the warming temps and increased solar today affected the East facing confined couloir in the middle of the Negatives Bowl.
• It was just spectacular with cutter blue skies and a pleasant temperature. At 11100ft it registered 21degF @ 12pm with a moderate 20mph westerly breeze. It was in the high 20’sF most of the day in lower elevations and there was a total absence of wind below ridgetop in the leeward side of the Negatives ridge
• Storm snow totals averaged around 6inches throughout the area and even at lower elevations ~8500ft compared to the Mammoth area yesterday. Once again 9500-9800ft seemed to be the magic elevation for seeing deeper accumulations. I found upwards of 8” in the Hemlock trees. Depth of snow in north facing terrain from 9-10000ft averaged around 100cm. Overall the snowpack in the Hemlock trees looked like a thin early season pack with much of the rock out croppings exposed and the northwest shoulder fairly devoid of snow at all. Fern Gully did not look to appetizing with multiple exposed reefs within the chute.
• The open alpine terrain on the Easterly face of San Joaquin Mountain was quite stripped and wind beaten.
• I investigated a primarily east facing couloir in the Negatives that was cross-loaded quite well with new snow. The cross loaded gully definitely had some stiffer new snow that was bordering on 4Finger hardness, but no amount of hard turns or ski cuts could cut anything loose. The most interesting part of the new layer of snow is that it was composed of around 15cm of 4Finger/Fist surface snow resting on a knife hard 2-3cm sun crust which then had another 10-15cm of soft Fist snow below it. This sandwich was all resting on the old set up snow from December. This ~30cm bonded sandwich felt hollow and sounded hollow as I plunged through the mid-layer sun crust, but again I could not get it to move, even on 38deg+ terrain.
• While checking out the snow in the couloir, it was quite warm and I could feel the amplified solar radiation. There was active minor roller balling beginning to shed from the southerly facing cliffs of the chute, this was at noon. The snow surface on this east aspect was neither moist nor sun affected at this point, but imagine by the end of the day there was a surface crust icing up.
• The new snow was very light on sheltered north aspects from the 10000ft level down. I did not find any slab in the area during my travels which lasted until 300pm or so.
• I skied to the valley floor and found some knee deep faceted snow on steeper due north terrain as well as a variety of temperature crusts on open panels of snow exposed to some sun. Coverage was still pretty good all the way down and for the most part supportable if you kept moving.