Descending from the East Ridge of Provo Peak at 10,500 feet, the first skier in our party triggered a shallow wet avalanche (WS/WL-D1-R2, 75 feet wide). It had characteristics of both a point release and a wet slab. It propagated slowly, and only a few feet at a time, spreading not like a wide slab avalanche all at once, but in a staggered manner, entraining snow like a sluff for 20-30 feet, then spreading out a bit wider all at once, then back to entraining. It took out all of the new snow (about 4-5 inches) down to the old slick consolidated snow underneath, but did not step down at all. It moved very slowly, and was never threatening. The starting zone was 40 degrees in steepness, and after the slope angle eased off a couple of degrees, the slab characteristics disappeared and the avalanche became a typical wet avalanche. Subsequent turns and slope cuts adjacent to the avalanche path, but lower in the sub-40 degree angled part of the slope did NOT produce any further movement in the snow. The debris traveled a few hundred vertical feet until the slope angle decreased to below 35 and stopped, forming a debris field about 2 feet deep. This particular slide was not destructive or even very threatening, however, on a longer steep slope, it could have entrained more snow and started moving faster, changing the potential hazard.
Closeup of debris field generated by the avalanche described above.
These are examples of the shallow avalanches from days prior to today. The first is lower elevation, about 8000 feet, and looks to be a point release that probably occurred on Wednesday. The second picture is higher, on the NW aspect of Lama Peak (east of Provo Peak) at about 10,500, and shows numerous shallow, small slab avalanches that occurred some time after the storms on Monday and Tuesday. None of these are particularly dangerous avalanches, but they do illustrate the poor bond between the old snow and new snow that will persist into Friday. This poor bonding creates potential for shallow dry slab, wet slab, and wet point release avalanches depending on aspect.
