Triggering large avalanches remains a serious possibility. Make conservative choices and approach avalanche terrain cautiously.
Shifting winds have redistributed recent snow into wind slabs on a range of aspects at higher elevations. Remain cautious where wind transport appears recent and where upside-down snow quality is evident.
A variable pair of weak layers exist below our recent storm snow (30-50 cm) and a bit deeper (40-80 cm). Depending on your location in the region, elevation, and aspect, these layers may present as either surface hoar (especially reactive) or a mix of facets and crust (not much better).
Avalanches on these layers are becoming less likely to trigger over time, however there have been signs that they are still reactive in certain locations. The variability and uncertainty about this problem warrants conservative terrain selection.
Dry cool conditions persist as a ridge builds over the region.
FRIDAY NIGHT: Cloudy, light south wind, temperatures around -8 C.
SATURDAY: Cloudy with some light flurries in southern parts of the region, light south wind, temperatures around -8 C.
SUNDAY: Mix of sun and cloud, light to moderate southwest wind, temperatures around -6 C.
MONDAY: Mix of sun and cloud, light to moderate northwest wind, temperatures around -8 C.
Few avalanches have been reported since last weekend, suggesting low observer numbers and/or a trend of the persistent slab avalanche problem becoming a low probability/high consequence scenario.
However, last weekend and last week there were many notable avalanches including natural, accidental, and remotely triggered avalanches up to size 2.5 at Pine Pass (one party of three was caught with two individuals partially buried and one fully buried). There was also reports of large natural avalanches at Torpy and Tumbler Ridge. Many of these avalanches ran on persistent weak layers currently found 30-80 cm deep throughout the region, so although these reports are a week old, they are still significant when we are dealing with a persistent slab avalanche problem.
Exposed higher elevations in the region have been significantly wind affected as the wind has shifted directions several times over the past week. As a result, new and recent wind slabs are suspected to exist across most aspects in the alpine and upper treeline. Wind slabs formed over the layers discussed below may be particularly reactive.
In more sheltered areas, 30-50 cm of snow from recent storms over has been settling well, with storm interfaces largely bonded, however variable weak layers exist below this storm snow. Depending on aspect, elevation, and location in the region, these weak layers may appear as especially touchy surface hoar (think shaded, sheltered spots) or as a combination of crust and weak, faceted snow (think of areas that may have been exposed to sun or rain). Reactivity at these interfaces has been variable. There has been compelling evidence these weak layers are widespread around Pine Pass, the McGregors, Hasler, and Tumbler Ridge. There has been less evidence around McBride and Renshaw, however our field team has found them in some isolated areas near McBride so we can not consider them entirely absent. We have little information from Kakwa.
A basal crust from November exists near the bottom of the snowpack in most areas. This crust may be a concern in shallow snowpack areas as well as in wind affected, thin-to-thick snowpack transition zones in the alpine.
Snow depths are in the 180-250 cm range around Pine Pass, the McGregors, and McBride, closer to 120-150 cm in the Tumbler Ridge area.
