Whumping and cracking at 7500'
Saturday 2/19/11 I skied up the hill behind Lee Vining and as I reached a steep convex area the snow collapsed under my weight. I turned and went around to the side, and when I reached the top of the steep convex area there was a whump and a crack shot 40 feet out and down the other side of the opening in the pinyons.
I dug down at my end of the crack and found 2 feet of new snow on top of large granular sugary rotten old snow. The buried sugary layer was thick and extended deeper than I could reach.
I ski this slope often over many years and this is the first time I've ever turned around due to avalanche concerns.
I went up again today where the snowmobiles had cut the slope yesterday, and the snowpack has stabilized considerably. I was only sinking in about half as deep as yesterday. When I got into the pinyons on the NE slope I triggered whumping and cracking again. I could look down on a skier's tracks from yesterday on the hill in back, and in one spot he caused a crack across the hill above and below a steep section--but it did not slide. This spot is just above the highest rope-tow pad and below the metal rope tow poles on the back hill. It is in the fog zone, maybe around 8000', where we had over an inch of hoarfrost coating the snow in early January. It is NE facing where two gullies intersect between pinyons and mahoganies.
Bartshe skied the gully on the right (yesterday?) and said at one point he stopped and the area collapsed, cracking and shooting snow out the bottom. He said Stella dug a pit (somewhere near the top on the left I think) and "it failed" and "she's not going to ski the slope anymore." Aren't you supposed to do that BEFORE skiing a slope?
Today I skied above the slope I originally skied Saturday and found no whumping, but similar snow profiles at the bottom near where the whumping and cracking occurred (the original crack has widened over 4 days). At the top, there is a very hard layer (difficult to punch through with a ski pole) between the new snow and the unconsolidated sugar beneath... in places. At the top around the SE side there is a 1" soft slab just barely forming on top. Wind gusts at sunset were already mobilizing small amounts of snow near the ridgetop.
It is a good thing these slopes aren't very steep because there have been a lot of people on them.
Greg Reis
Lee Vining, CA