Carefully evaluate big terrain for overhead cornice hazard and areas where wind slabs may remain reactive to human triggering.
The overnight change in wind direction from southwest to northwest may have loaded new features which may be sensitive to human triggering.
Significant cornice growth has been observed. Recent natural and explosive triggered cornices have produced large avalanches (size 2-3). Avoid overhead cornice hazard and stay well back from lee side of ridges.
Sunday night: Flurries bringing 5-10 cm new snow. Moderate northwest wind. Freezing level valley bottom.
Monday: Sunny. Light north wind. Alpine high -12 C. Freezing level valley bottom.
Tuesday: Flurries bringing up to 5 cm new snow. Light wind building to strong northwest at ridgetop. Alpine high -6 C. Freezing level valley bottom.
Wednesday: Flurries bringing up to 5 cm new snow. Strong west wind at ridgetop. Alpine high -2 C. Freezing level rising to 800 m.
On Saturday, a widespread natural cycle and extensive explosive work produced cornice and storm slab avalanches size 2-3.
Natural and explosive triggered deep persistent slab avalanches size 3-4 have been reported in the Lillooet River valley north of Pemberton, at the eastern border of the region.
Extreme southwest wind during the storm has scoured windward aspects, formed loaded pockets up to 150 cm deep in alpine lees and contributed to rapid cornice growth. Below 1900 m, recent snow overlies a thick crust and tapers quickly with elevation.
Weak faceted grains and crusts near the base of the snowpack have not been an active avalanche problem recently, despite significant new snow loads. They are still on our radar, especially in inland parts of the region.
