Avalanche Forecast

Issued: Mar 27th, 2018 4:56PM

The alpine rating is considerable, the treeline rating is considerable, and the below treeline rating is moderate. Known problems include Storm Slabs.

Avalanche Canada cgarritty, Avalanche Canada

Strong winds have been forming new wind slabs while the bond below all that new storm snow still doesn't inspire much confidence. Err on the side of caution as we transition out of the storm.

Summary

Confidence

Moderate -

Weather Forecast

Wednesday: Mainly cloudy with isolated flurries and a trace of new snow. Moderate to strong west wind. Freezing level to 800 metres with alpine high temperatures around -4.Thursday: Cloudy with flurries bringing about 10 cm of new snow by end of day, increasing overnight. Moderate to strong south winds. Freezing level to 800 metres with alpine high temperatures around -3Friday: Cloudy with continuing isolated flurries and a trace of new snow. Light west winds. Freezing level to 900 metres with alpine high temperatures around -4.

Avalanche Summary

There was a report of a small (size 1) skier-triggered storm slab on Sunday that occurred on a north aspect at 1400 metres. The slab was 40 cm deep and failed on a recently buried layer of surface hoar. Numerous natural wind slab and storm slab releases from size 1.5-2.5 were observed from the highway in Bear Pass. Poor visibility has continued to limit observations throughout the region.Reports from Saturday showed ski cutting in the Bear Pass area producing both slab and loose dry avalanches to size 1.5. Slabs failed all the way down to the melt-freeze crust buried 60 cm deep at treeline on north aspects.On Saturday, the strong westerly winds were responsible for triggering a couple of wind slabs up to size 1.5 from north-easterly aspects in the alpine. On Friday and MIN reported a rider triggered wind slab avalanche size 1.5 from a southwest aspect. The person rode out of the avalanche and the crown was reportedly 35 cm deep. Friday also saw a natural cycle up to size 2.5 in the recent storm snow.

Snowpack Summary

Stormy weather brought 50-80 cm of new snow to the region over the past week. These accumulations taper quickly toward lower elevations as well as moving inland from the coast. At high elevations, strong southwest winds have been promoting the formation of storm and wind slabs. Beneath the wind effect, the storm snow overlies old snow surfaces that include a layer of surface hoar existing on high shaded aspects as well as a melt-freeze crust on all aspects at treeline and below. The bond of our storm snow to this layer remains a concern, with the consequences of shallower storm slabs or wind slabs 'stepping down' to this deeply buried interface currently being very high.Deeper in the mid-pack, layers of crusts, facets, and isolated surface hoar buried 50 to 100 cm exist from mid- and late-February and a surface hoar/ crust layer from January is buried around 150 to 200 cm. Near the bottom of the snowpack, sugary facets exist in colder and dryer parts of the region, such as the far north. These buried layers are currently dormant.

Problems

Storm Slabs

An icon showing Storm Slabs
A series of storms has layered thick storm slabs over the region while more recent strong west winds have built up new wind slabs. Very large avalanches may result if shallower slabs step down to the old snow surface buried 50-80 cm deep.
Watch for signs of instability such as shooting cracks or recent avalanches.Be especially careful with wind loaded pockets near ridge crests and roll-overs.Use conservative route selection, choose moderate angled and supported terrain with low consequence.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 3

Valid until: Mar 28th, 2018 2:00PM