Mushroom

This was a sunset walk after an overlong post-forecast nap. My primary objective was to look at the amount of recent melt to help predict how wet problems will unfold on Monday.

I did not experience any cracking or collapsing. I kicked at some stiff, recently formed drifts that were well-attached to the surfaces they rested on.

Tons of snow left in trees, large trees with southerly exposures had long icicles hanging in them (great sign of a gradual melt at cold temperatures). A stiff crust formed at the snow surface this weekend, thanks to periods of sun and clouds at cold temperatures. This crust was fairly homogenous across the solar aspects that I traveled through; ~5cm thick, aerated, kind of supportable. We did a good bit of gentle melting this weekend and have likely been getting to the point of small human-triggered slides becoming possible in steep rocky terrain, but mostly we've avoided a wet snow problem, so far. 

At middle and upper elevations, there is a major sun and rain crust beneath the recent snow. This crust began to form on Monday thru Wednesday of last week (as a sun crust/MFcr), and then received significant rain up to and above 9,000' on Thursday. Precip switched to all snow on Friday. The snow that has accumulated on top of this crust has started to melt and bake on, but will likely be shed easily when the sun returns in force on Monday. I expect it to take a bit of time for things to really warm up, but once they do we will see quite a bit of shedding, likely lasting through the day and following the sun around the compass. I anticipate wet loose slides to become large and destructive in large terrain. Slides running on top of the crust will move fast and far. The recent snow has settled into a dense slab in many locations and these surface slides may flank out and have a slabby character to them.  I expect most of the wet snow activity to take place above this crust, on Monday at least. However, the snowpack underneath the recent snow is still saturated from Thursday's rains. As the week progresses I expect to see more slides failing deeper in the snowpack, gouging down through wet snow and flanking out as slabs. 

The snowpack on shaded aspects above ~10,000' is on its own program. Here, no rain fell and the snow has remained dry and cold. Several generations of wind slabs have formed in the past week and these are sitting on a variety of surfaces. One week ago, skiers were easily triggering small slabs that failed in this terrain. The weak layers that produced these were typical of variable spring weak layers - crusts with facets on solar margins and thin facet bands on shaded slopes. These are buried underneath several inches of SWE (several feet of snow) in this zone. While I don't expect these to pose a widespread or longterm problem, I am still considering them in my terrain selection. Also, there is a big question mark with the upper elevation rain event from Thursday. There may be a narrow band where a relatively small amount of rain fell on dry snow, producing melt-layer recrystallization facets. I have not directly observed these, and the problem would  be isolated to a narrow band of elevation on the cold side of the compass.