Not trying to set the record straight or anything like that, but wanted to provide some other info. From NWAC gathered info via ski areas patrollers, Highway avalanche folks and the staff, many areas of the Cascades (and Olympics) have experienced and are experiencing significant faceting...both above a slightly decomposing mid-upper pack crust (near surface facets) and below the crust to ground (beginning to intermediate faceting, not depth hoar yet...at least for most Cascade west side areas). However, as noted in the Mission Ridge post earlier which indicates facet farming is alive and well in some locations, much of the generally shallower Cascade east slope pack is dominated by facets and quite sugary with some true depth hoar likely (well developed columnar shapes).
In general faceting occurs most quickly for a given gradient at temps close to freezing, since the vapor pressure is highest there (more vapor to be deposited or transferred as new facets) and change in vapor pressure per degree temp change is highest (so the highest vapor gradient). Hence the development of facets or depth hoar near the ground where it's normally close to freezing. This gradient in the snowpack is by no means static or average, with local maximums often above higher density layers like crusts (the crust conducts the heat well, but the lower density snow above the crust does not = high gradient). Below crusts, the vapor is deposited because it accumulates (has nowhere to go since the crust provides a cap). Anyway, the current thought is that with future more normal Cascade loading (snowfall at intermediate freezing levels), the near surface facets or surface hoar will provide plenty of failure planes (and for sensitive slabs with symapthetic fractures, remote triggering, cracking and whumpfing), and in areas where a shallower and more faceted snowpack exists throughout, there could be climax slides to ground. Anyway, for what it's worth....
