Quick report
- Aspect
- North
- Red Flags
- Heavy Snowfall
- Elevation
- 2896 m
- Slope Angle
- 35°
- Red Flags Comment
- <p>Insane snowfall rates this morning produced easy sluffs on steep (37+) slopes. However, due to calm conditions, no slab formed in the new snow (as of 12pm) so conditions were manageable for skilled parties.</p>
We have a good looking snowpack in Snake Creek above 8000 feet with a 1.5m depth and a couple of weeks of warm temps. Old surface hoar (4F) near the ground is the only interruption in solid 1F rounds all the way to the ground. Although those old facets are noticeable, they are not conspicuously weak and appear to be bonding nicely. Of course, if the storm continues producing at the prodigious rate of this morning, the buried facets should be viewed with renewed interest. But for now, the danger remains confined to the new snow.
In case anyone doubts my claim of 10 inches in 2 hours, here is a photo of the snow piled up on my snowmobile seat while I was skiing. Mitten included for scale.
Snowpack
- Instability Comment
- <p>Like clockwork, at 37 degrees steepness, moderately long running sluffs could be initiated with a simple push from a ski. These sluffs spread and entrained snow as long as the slope angle remained 37, but stopped quickly once the angle eased off. I observed one natural during my descent that ran at least a few hundred feet and was a bit unnerving.</p> <p>Ski cuts at rollovers were mandatory and effective for managing the hazard, but continuous steep slopes would be quite hazardous. Despite the warm air temperature, the new snow was not cohesive enough to form a slab so the danger was limited to sluffing (for now). </p> <p>Note that this benign setup cannot be extrapolated to areas further south that did not receive as much Christmas snowfall.</p> <p>I expect that with additional snowfall in the late afternoon, the hazard presented by the sluffing in the new snow will increase considerably, and will be more difficult to manage. If the snow becomes cohesive overnight with warm temps then it could be seriously dangerous, with tempting riding conditions and no natural triggers, but just the right stress/strength balance to allow a skier to trigger small slabs in steep terrain that could easily entrain lots of snow and become large, dangerous avalanches. I would not walk up underneath 35+ terrain tomorrow, but might consider skiing it from the top if the "no slab" conditions were verified with digging and slope cuts. As such, I'm calling the hazard considerable.</p>
4-6 inches from Saturday/Sunday, plus 10+ from today sat on top of the consolidated surface from the high pressure period. Bonding to the old snow surface was good, but internal cohesion was not good and sluffs were worringly easy to initiate on steep slopes.