New wind slab development over a weak, facetted mid pack remains a concern. Warming temps and solar may increase sensitivity of this problem.
Sheltered areas hold some descent boot top; open areas variable and wind hammered.
Previous N winds have caused reverse loading and wind slabs down into the tree line; present strong SW winds continue to add to this problem. Main concern is where wind slab has built over weak faceted snow. Watch for hollow sounding snowpack.
December's persistent weaknesses sit over different layers depending on elevation and aspect. Below 1950m, a faceting rain crust is roughly 40-60cm down. Above 1950m, a buried surface facet layer down 20-30cm is the primary concern.
Friday: Mix of sun and cloud isolated flurries - freezing level valley bottom - alpine high -8 C, winds west 15 gust to 55km/hr.
Saturday: Mix of sun and cloud - freezing level up to 1500m - alpine high -5 C, low -9 C; winds light west.
Sunday: Mix of sun and cloud - freezing level up to 1400m - alpine high -5 C, low -9 C; winds west 15 gust 50km/h.
Previous N and present SW winds scouring terrain and adding to wind slabs ALP and open TL. The mid-pack is highly faceted with active persistent weak layers from Dec. Interfaces within the facets found down ~30cm and ~60cm. These layers have varied sensitivity but if triggered can build large, destructive avalanches. Cornices are building.
Several large avalanches were observed on Tuesday around the Churchill Range to sz 2.5 in the alpine - some running to ground. Patrol south on Thursday noted no new activity in the poor lighting but significant wind effect and drifting evident at all elevations. Uncertainty exists re sensitivity of our slab problem in the alpine and at tree line.
