While these deeper snowpack zones seem to be a bit better than the rest of the forecasting region, concern remains for the persistent weak layers to be human triggered from shallow or rocky areas, or for them to be triggered by large loads, such as a falling cornice or moving avalanche.
Moderate terrain choices with limited overhead hazard continue to be the best way to manage the uncertainty in the snowpack.
Watch for hazard ratings to rise Monday with a warm, wet Pacific flow incoming.
Three persistent weak layers formed in January are down 60-110 cm. Buried sun crusts found on steep solar slopes present the greatest concern for triggering on these interfaces however weak facets and isolated surface hoar can be found on the same interfaces on shaded aspects.
Weaker facets and depth hoar remain at the bottom of the snowpack and inspire little confidence. Be especially cautious in thin snowpack, or rocky areas, where triggering is more likely. Large loads such as cornice failures or smaller avalanches may act as a trigger for this layer so careful consideration of the terrain you travel beneath is wise.
Not much avalanche activity has been observed in this area during the past week, however in the thinner snowpack areas of the BYK region, we continue to see significant avalanches on the different persistent layers.
A sun crust is present on steep solar slopes at treeline and below while 10-30 cm of soft snow can be found on northerly aspects. The various January persistent weak layer interfaces (sun crusts, facets, and surface hoar) are now down 60-120 cm. The weaker Nov. 16 basal facet layer is down 110-170 cm and continues to produce whumpfing and moderate to hard sudden collapse results in snowpack tests.
Mainly cloudy skies with trace amounts of accumulation will persist overnight Saturday through Sunday with west-southwest winds peaking near 30km/h and alpine temperatures warming a bit to between -10 and -15C.
Sunday evening snowfall will increase to bring 5cm overnight as winds increase to 40km/h and shift southwest and a strong Pacific flow of moisture begins.
10-20cm of snow is expected Monday with freezing levels approaching 2000m and winds increasing to beyond 50km/h.
