As winds pick up ahead of the next storm, fresh, reactive wind slabs will likely form at upper elevations. The region continues to deal with a tricky persistent slab problem and very large avalanches remain possible. Conservative terrain selection remains essential.
Plenty of recent, low density snow is available for transport as winds pick up ahead of the next storm. Fresh wind slabs overlie a weak interface which could result in them being particularly touchy and remaining reactive for longer than usual.
A persistent slab problem formed by a crust down 70-130 cm has created a low likelihood, high consequence scenario that is difficult to forecast. Avoid likely trigger spots such as steep, rocky slopes with a shallow or thin to thick snowpack.
Wednesday night: Increasing cloud. Light NW wind switching SW. Treeline temperature around -22 °C.
Thursday: Light snowfall 3-6 cm. Moderate SW wind. Treeline high around -14 °C.
Friday: Snowfall 5-10 cm. Moderate to strong SW wind. Treeline high around -4 °C.
Saturday: Snowfall tapering 5-10 cm. Moderate SW wind. Treeline high around -10 °C.
On Monday and Tuesday, natural storm slabs and loose dry avalanches size 1-2 were observed out of NE-SE aspects in the alpine. Explosive triggered storm slabs were observed up to size 2 and ski cut up to size 1.
The persistent slab problem continues to produce sporadic and spotty activity in the South Rockies and nearby regions.
The region typically received 20-30 cm of new snow from the recent storm. This new storm snow buried a highly wind affected snow surface and widespread facets from the recent cold conditions which may create a weak bond with the new snow. The new snowfall was accompanied by moderate to strong winds at higher elevations and the new storm slabs are expected to be most reactive in wind loaded areas in the alpine.
The most notable layer of concern in the snowpack is a crust that was formed in early December and is now typically down 70-130 cm. In the past week, we have seen explosive triggered activity on this layer as well as snowpack tests that have shown that the layer remains reactive. Neighbouring regions have seen very large avalanches on this layer over the past week. This layer has created a low likelihood, high consequence scenario which is best managed through conservative terrain choices and disciplined backcountry travel techniques.
