The danger ratings don't tell the whole story. Uncertainty regarding the Deep Persistent Slab problem would have me avoiding any large or committing features.
Up to 20 cm of recent snow accompanied by strong winds and warmer temperatures formed wind slabs.
These wind slabs remain reactive to rider traffic. Expect them to be most reactive where they sit on top of a crust or a surface hoar layer. There are a few of these layers that vary in depth and distribution across the region.
Be cautious at ridge crests and on convex rolls.
Warm temperatures could keep the upper snowpack unstable at lower elevations. Use caution around steep, rocky start zones, especially if they see the sun.
The early December crust can be found 140-200 cm deep.
This deep persistent slab problem has been less active over the weekend, but we have been reminded multiple times in the last month that this layer could remain a concern all winter.
Thin rocky start zones are the most likely place to trigger this layer. Also, daytime warming, solar radiation, cornice fall, and step-downs from smaller avalanches could increase the chance of an avalanche on this layer.
Sunday Night: Mostly clear. No new snow expected. Moderate northwest wind trending to strong at higher elevations. Above freezing layer breaking down. Freezing level dropping to near valley bottom, alpine low around -3 C.
Monday: Mix of sun and cloud. No new snow expected. Moderate northwest wind trending to strong at higher elevations, but tapering off over the day. Alpine low around -5 and freezing levels rise to around 1250 m late in the day.
Tuesday: Mostly sunny. No new snow expected. Light southwest wind trending to moderate northwest at higher elevations. Freezing levels at valley bottom overnight, and rising to 750 m through the day.
Wednesday: Partly cloudy. No new snow expected. Moderate northwest wind trending to extreme at higher elevations. Freezing levels at valley bottom overnight, and rising to 750 m through the day.
On Saturday, there were several reports of snowballing/pinwheeling/point-releases, a few small cornice failures, and small, loose-wet avalanches on steep solar aspects.
On Friday, several natural wind slab avalanches were reported in Kootenay Pass. They were mostly on northeast aspects at treeline.
On Thursday, numerous storm slab avalanches were reported up to size 2.
During the warm previous storm, mid-last week, a large widespread avalanche cycle occurred with most avalanches releasing within the storm snow and some on Jan 11 surface hoar layer. Strong solar radiation and warm temperatures were also at play after the storm, producing numerous avalanches at all elevations and scouring avalanche paths to the ground in places.
There are reports of a new surface crust on steep solar aspects from the warm temperatures and sun on Saturday, and surface hoar growing in sheltered areas.
10-20 cm of recent snow combined with strong winds formed wind slabs and buried a series of recent surface hoar layers and melt-freeze crusts found down 15 cm and another down 25 cm. These extend to 2400 m and are most prevalent (thicker) on southerly aspects.
Digging deeper, down 50-60 cm is yet another surface hoar layer that has seen recent avalanche activity. A well-consolidated mid-pack exists below this and above the early December crust/facet interface.
The early December crust/facet layer has been responsible for sporadic but very large, persistent slab avalanches over the past month. The crust is now buried 120-200 cm deep except in thin, wind-affected areas near ridgetops. Daytime warming, sun, cornice fall, and smaller avalanches through the forecast period may be enough to wake this layer up and initiate large to very large avalanches.
