Quick report
- Aspect
- Northeast
- Red Flags
- Recent Avalanches, Wind Loading, Poor Snowpack Structure
- Elevation
- 2865 m
- Slope Angle
- 26°
- Red Flags Comment
- <p>Slide this morning on Patsy Marley was a hard slab due to recent wind loading, failing on faceted snow down near the ground.</p>
Photo is of unopened terrain at Alta showing obvious signs of wind loading. Video is extended column test showing full propagation with failure down near the ground.
I went in to Grizzly to deploy some thermocrons to measure temperature gradients in the snow surface for our unwelcome period of high pressure. Decided to wander up to Twin Lakes pass to look at slides from this past weekend and noticed the slide that occurred earlier in the morning. (It had been reported, so I did not submit a separate observation.) According to Brett Kobernik, it was remotely triggered. It was an obviously wind loaded slope that was just waiting for a trigger. It failed in the weak faceted snow near the ground, and was a a pencil-hard slab with nasty chunks of debris.
Photo is showing the debris with the remnants of ski or skin tracks. Video is at crown showing the obvious weak layer down near the ground.
Overall poor stability tests and recent avalanches did not make me feel much better about our current snowpack. It seems our current weakness in the bottom 20-30 cms of the snowpack are going to be with us for awhile.
The glass-is-half-full view is that we actually have decent coverage and reasonable snow depths should begin to help heal our basal weaknesses from getting worse. We will have to watch what happens at the snow surface over the next few days as near-surface faceting is likely.
The glass-is-totally-full view is that our Wasatch looks absolutely beautiful right now. Happy Thanksgiving!
Snowpack
- Instability Comment
- <p>I was hopeful the weekend storm would help put the faceted snow and depth hoar in the bottom 20-30 cms (8-12") to sleep, but apparently not. I was still getting full propagation failures in extended column tests, with the best scores coming in at ECTP17, and ECTP6 on the low end; all were Q1 shears. (Video below.)</p> <p>It seems the strong winds from the past few days have overloaded some upper elevation shady slopes producing avalanches failing in the weak faceted snow down at the ground. Slide on Patsy Marley is a prime example.</p>
HS in upper LCC is about 90 cms (36") and supportable. Winds from past two days took a toll on the snow surface where soft snow is hard to come by. Did find some thin rime crusts on a few NW aspects. South aspects were becoming damp when I was exiting the canyon in the early afternoon, and some rollerballs were noted. Fortunately low sun angle is preserving many slopes from the sun.