Avalanche Forecast

Fair - Timing, track, or intensity of incoming weather is uncertain

A broad upper trough remains just offshore while a cooler, unstable onshore westerly flow will persist and strengthen through Monday. A multitude of systems will bring light –moderate precipitation, and strong SW winds, while the arctic air should be pushed out of the region by Monday. Monday into Tuesday will see the heaviest amount of precipitation during the forecast period. Monday: Fzlvl’s 400 m, snow amounts 5-10 cm, ridgetop winds SE 15- gusting 60 km/hr, and alpine temps -8.Tuesday: Fzlvl’s 500 m, snow amounts 15-25 cm, ridgetop winds SW 30-gusting to 70 km/hr, alpine temps -7.Wednesday: Fzlv l’s surface, snow amounts near 5-10 cm, ridgetop winds S 30 km/hr, and alpine temps -9.

On Thursday: a report of a skier triggered size 1.0 occurred on a E-SE aspect @ 1180 m, down 10-40 cm and 15 m wide, on a convex cross-loaded terrain feature. Explosive control performed in the region also triggered several size 1.0-1.5 slab avalanches, 25 cm deep, 30 m wide.

Recent observations suggest that the alpine is fairly wind hammered from the steady, moderate SE winds. Hard slabs, storm, and wind slab instabilities exist at treeline and in the alpine.  Hard slabs are harder to trigger, but may have larger consequences due to wider propagations. Storm and wind slabs may be touchy to rider triggers; especially on leeward slopes and behind terrain features where pockets of wind slab easily build. A couple recent test results done in the upper storm snow show an easy (RP) shear down 20-25 cm and a hard (RP) down 80 cm. The mid-pack is gaining strength and is well settled.Digging down deeper is the early November facet/crust layer. This crust sits near the base of the snowpack, and recent tests done in the Bear Pass area around 1100 m have shown this layer to be unreactive. Testing done in the Shames area on this interface have also shown no results, with moist snow below.Total snowpack depth is probably around 150-180 cm at treeline, and deeper but more variable in the alpine. The snowpack at below treeline elevations is reported to be strong.