New snow and wind will form fresh slabs at upper elevations. A couple of near-surface crusts offer slick sliding surfaces for avalanches. As the storm slab problem gets trickier, the easiest solution is to choose more conservative terrain.
New snow and wind are forming fresh slabs. Where previous days' snow sits over a weak layer, slab avalanches could be larger than expected and run far on a slippery crust.
Tuesday: Rain turning to snow 15-20 cm. Strong southwest wind. Freezing level 1500 m and dropping.
Wednesday: A mix of sun and cloud. Strong southwest wind. Treeline high temperatures around -5. Freezing level 800 m.
Thursday: A mix of sun and cloud. Light northwest wind. Treeline high temperatures around -5. Freezing level 500 m.
Friday: New snow 10-15 cm. Strong southwest wind. Treeline high temperatures around -3. Freezing level 700 m.
No recent reports.
15-20 cm of overnight snow fell amid strong wind, likely loading deeper deposits into lee features at upper elevations. The new snow may sit over a thin lens crust that formed when 10-15 cm of recent snow warmed up on Tuesday. This recent snow may be sitting over a weak layer of surface hoar crystals near or on a thick crust. See photos of the surface hoar before it was buried in this excellent MIN report from Sunday.
Treeline snow depths in advance of the atmospheric river were around 80-100 cm but rain has eroded some of this. Much of treeline and almost all below treeline elevations are still below threshold depths for avalanches.
