Quick report
What a day in the Alpental Valley. As many obs have already noted, it was warm and the recent storm snow was quickly destabilizing. After a walk up the valley by the proper route, we raced up to the Thumbtack, trying to beat the sun's influence on the rocky slopes of Chair Peak's shoulder. We got there just as snow was starting to shed from rocks, trees, and cliffs, and were able to scramble up to the ridge before any real damage was done.
Our first impression was that the North Slope was heavily wind-loaded, and we kept to the well-supported slopes down toward the top of the Cache Couloir. It was at this point that we glanced over to the North Slope proper, where multiple parties were apparently ready to tee off on the slope without much worry. Two turns into their descent, out comes a large slab avalanche on a convex feature. Apparently, they didn't notice the numerous natural wind slabs we observed in the Upper Chair Peak Basin or on the shoulder feeding into the North Slope proper. When asked about the slide, the party simply replied that it was no big deal and didn't run too far. Photos later proved otherwise, since the slide ran almost full path and ripped out additional slabs on the descent.
The snow got progressively warmer and heavier, even on the north aspects of Chair, and we were easily triggering rollerballs and pinwheels, some growing large. We exited the way we came, ready to test the sunny slopes to see if it was ready to push wet loose slides. We got a few small pockets to go, and it was certainly heavy, but it wasn't quite the right set-up to push. However, we crossed several debris piles and saw actively shedding snow throughout our descent, which made skiing challenging until we reached Source Lake.
The out track back to the parking lot is in great shape.
Weather
Low-level inversion clouds in the valley with high clouds above. The sun was streaming through the high clouds with full bluebird conditions here and there. Warm!
Snowpack
The snowpack is now heavy and moist on all but the darkest slopes as the April sun did its thing.
I dug relatively high on the North Slope, where there is admittedly some wind-loading, and found 55cm over the 3/25 crust. An obvious interface down 32cm is likely the 4/1. Just above the 3/25 a second subtle melt-freeze crust exists with some weaker snow between it and the 3/25.
I did not receive any significant snowpack results.
Avalanche
There were numerous natural slab avalanches observed throughout the upper Alpental Valley, particularly in the Chair Peak area. We also witnessed the AMGA course trigger a large wind slab on a convex feature on the North Slope of Chair Peak. Around midday, rollerballs and pinwheels transitioned into actual wet loose avalanches on sun-exposed slopes.