Storm slabs will likely be building and becoming increasingly reactive throughout the day with new snow and wind.
A persistent weak layer from December may "wake up" this weekend and produce avalanches again with the new snow load. Maintain a conservative approach to terrain.
Weak surface hoar and/or faceted grains sit above a melt-freeze crust 50 to 100 cm deep. Be aware that new snow and wind will be adding additional load to this layer, and it may become reactive again this weekend.
Storm slabs may become increasingly reactive throughout the day.
FRIDAY NIGHT - Snow, 10-15 cm / southwest wind 30-60 km/h, gusting to 80 km/h / alpine low temperature near -4 / freezing level 1000 m
SATURDAY - Snow, 10-15 cm, with another 15-20 cm overnight / southwest wind 40-60 km/h / alpine high temperature near -3 / freezing level 1100 m
SUNDAY - Snow, 5-10 cm / southwest wind 30-50 km/hr / alpine high temperature near -3 / freezing level 1500 m
MONDAY - Snow, 10-15 cm / southwest wind, 20-30 km/h / alpine high temperature near -3 / freezing level 800 m
Storm slabs may become increasingly reactive throughout the day on Saturday as the new snow adds up.
With new snow piling up over the weekend, the chances of a resurgence of persistent slab avalanches will increase. Without a big dump of snow over a short period of time, this incremental loading will likely make it difficult to predict when this layer may once again reach a tipping point and start producing avalanches. This problem is best managed with conservative terrain selection.
There were numerous size 1-2 explosives triggered storm slab avalanches reported in the region on Thursday.
20-30 cm of new snow is expected between Friday night and Saturday afternoon, bringing total recent snow amounts to 30-50 cm. Storm slabs will likely be building throughout the day.
Two weak layers are buried in close proximity to one another. They are 70-100 cm deep around Nelson and 50-80 cm deep around Rossland and other western parts of the region. The layers are composed of feathery surface hoar and sugary faceted grains and they overlie a hard melt-freeze crust.
The new snow load expected over this weekend will likely increase the chances of large avalanches running on this layer.
