Regions
Kootenay Boundary.
A dramatic shift in the weather will increase avalanche hazard fairly rapidly once it starts to snow. If you see anything of interest, remember to let us know by submitting an observation using the CAC Mobile app.
Confidence
Fair - Timing, track, or intensity of incoming weather system is uncertain on Tuesday
Weather Forecast
Synopsis: A strong Westerly offshore flow pattern is becoming established which is allowing a series of systems to come through for the remainder of the week. Tonight and Monday: A first frontal system approaches later Monday spreading light precipitation to the region. 5-10 cm of snow amount are forecasted with winds increasing to strong from the SW. Freezing levels are forecasted remain at the surface.Tuesday: Another, stronger system moves across the region spreading moderate amounts of precipitation with strong SW winds. Freezing levels are forecasted to rise to 1000 m briefly. Precipitation amounts are forecasted to be from 15 to 20 cm.Wednesday: Another system is forecasted to come through, expect moderate to heavy precipitation with similar freezing levels.
Avalanche Summary
There has been a report of a skier triggered slab avalanche size 1 on an E facing slope and of loose snow avalanches size 1 on S and N aspects. Expect more and bigger avalanches this week with the incoming weather.
Snowpack Summary
Snow should start falling tomorrow during the day, slowly adding load to the snowpack. Avalanche conditions will aggravate during this bulletin period with the moderate to heavy forecasted load (possible total of 30 mm in water equivalent) and strong SW winds. The new snow will fall on a variety of weak layers such as surface facets, on a new surface hoar layer in sheltered areas, on a crust on solar aspects or on hard windslabs in the alpine. The bond of the new snow with these surfaces is expected to be poor. 10-30 cm below exist another surface hoar or suncrust layer that has been reactive to skier traffic even since it has been buried in late January. Keep in mind that the storm snow could remain unstable for a period longer than usual because of the persistent underlying surfaces. The mid snowpack is strong and supportive. Deeper persistent layers have been dormant, however, they could wake up again with the large load forecasted.
Problems
Storm Slabs
Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.