Professional Observation

Observation Details

Signs of Unstable Snow

Snow Stability

Key Points

Toured on a variety of aspects in the Mammoth Lakes Basin today between 11000′ and 8600′.

It was a chilly 15F at 11000′ at 10:30 a.m. with very light SSW wind. We skied a ribbon of snow on a South facing aspect from 11000′-9200′ with a trace amount of new snow on top of frozen chickenheads. Getting to the snow required a bit of walking through scree! Some small rollerballs were coming off of turns but the snow did not feel sticky. Much of the surrounding solar terrain was snow free or highly wind affected. Turning more East on lower angle terrain below tree-line we found 2-4″ fresh snow on a supportable old surface. Climbing back through East facing terrain around 1130 the snow was beginning to get moist in the sun and trees were dripping.

North facing trees held the most snow and softest surfaces. The new snow had obviously settled, but around 6″-8″ of F hard snow was pretty consistent. I stomped on several steep rolls along an exposed, corniced ridge with a good fetch for snow transport from W to E, and  could get no cracking or slabs of snow to release on the steep E side. The only thing resembling a wind slab that I found approaching tree-line were small panels of wind pressed snow on windward terrain features that cracked, but any cracking was confined to my skis. Kick turn tests and repeated hand shears performed at the old snow/new snow interface all were negative. The new snow seemed to be bonding to the 4F hard faceted snow beneath.

Descending back to Tamarack around 1:45 E aspects below tree-line had developed a zipper crust. New snow depths were less approaching Twin Lakes, but some decent dust on crust skiing could still be found on N aspects.

Winds were calm to light out of the SW with below freezing temperatures and clear skies throughout my tour from 10:30 to 2:15. It was a beautiful day to be out and so very refreshing to be skiing soft snow!