East and southeast winds yesterday and overnight found plenty of nice soft powder to drift at upper elevations. We've noticed the rapid development of small grained near surface facets and frost crystals or surface hoar on the snow surface in the past few days. Once buried, these can become thin persistent weak layers. Drifting yesterday created sensitive wind slabs on top of weak surface snow, and a few parties in different areas in the zone observed natural avalanches...
We're keeping an eye on the snow surface these days, since weak layers commonly develop on or near the snow surface during high pressure conditions. We watched as V Feathery surface hoar or frost crystals grew on the snow surface during the day yesterday. (12-31-2015)
The Tony Grove Snotel at 8400' reports an inch of new snow from overnight and 11 degrees. The station reports 21 inches of settlement in the last week (since Christmas Eve), and there's now 49 inches of total snow, containing 98% of average water content for the date. It's 11 degrees at the 9700' CSI Logan Peak weather station, which is showing southeasterly winds averaging close to 30 mph with a 49 mph gust early this morning.
Parties on New Years Day reported significant drifting and observed fresh natural wind slab avalanches in Wood Camp and Logan Dry Canyon, and and a skier reports triggering a fresh wind slab near Millville Peak in Providence Canyon.
A fresh triggered wind slab avalanche in Providence Canyon and a natural in Wood Camp. (observers 1-1-2016)
Evidence of significant natural activity from the productive pre-Christmas storm is widespread across the Logan Zone. Most of the natural avalanches occurred early in the storm, but there are also a few that appear to be a bit more recent.
- On 12/19 an experience local rider was caught and carried through trees, mostly buried, and trapped by an avalanche he triggered above the Tony Grove Campground. Video Report
- On 12/20 a skier remote triggered a large Deep Slab avalanche high on the south rim of lower Logan Canyon.
- I observed several large more recent avalanches in the upper Providence Canyon area on Saturday. I think these were Christmas Eve naturals, but they might've been remote triggered, unseen by riders in limited visibility. Video Report
***To view our updated list of backcountry observations and avalanche activity from around Utah, go to our observations page