The PWL problem seems to be focused on slopes that have been wind-loaded where you have a stronger slab on top of the weaker facets below. The photo and video below show full propagation of an ECT on a west aspect at 10,000' in upper Big Cottonwood. This slope had a hard, 1F slab on top of weaker facets. I repeated the test with scores of ECTP11, ECTP17, and ECTP19. This tells me it is possible to trigger an avalanche on slopes that have this structure of strong-over-weak.

South-facing slopes in Big Cottonwood have mostly melted out. Once we do get enough snow (and we will!), the south-facing slopes will be safer alternatives as they have no weak snow.