Here are a series of photos of the problem layer in Rogers Pass and its potential.
First photo clearly shows the crust down 50 cm on a south aspect in the forest at 1900 m. Not obvious is the surface hoar layer above it and the facet layer below.
Second photo shows how the layer failed as I walked uphill beside it, before we even cut the sides and back of the block. Rustchblock score of 1, whole block.
Third photo shows a small surface hoar crystal, pulled out of the layer that is the problem.
Fourth and fifth photos are of a small skier-triggered avalanche nearby. Note that there was no crust on the slope where this occurred, just the surface hoar layer, and therefore pretty hard to identify without some determined investigation of the snowpack.
This is going to be an ugly layer. It was not very reactive yesterday because the slab on top of it is very soft. A little bit of wind, a slight increase in temperature, or just a little bit of time will all make the slab settle slightly and cause it to be more reactive. There is a good chance that this settlement will be slow and subtle and will catch us by surprise.
PCs sometimes have problems viewing my Mac attached photos, if you can't see these photos you can view them on the website, link below.