Avalanche Forecast

Issued: Apr 1st, 2015 8:55AM

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

ccampbell, Avalanche Canada

South Coast.

Deep persistent weaknesses are still reactive in snowpack tests. Very large avalanches are still possible.

Summary

Confidence

Good

Weather Forecast

Unsettled weather is expected to bring a mix of sun and cloud with isolated flurries on Thursday, before a more organized system brings 5-10 cm of snow on Friday and another 3-5 cm on Saturday. Freezing levels are expected to hover around 1500 m for the forecast period and winds are expected to pick up to moderate southwesterlies during on Friday.

Avalanche Summary

Over the past few days, several natural wind slab avalanches to Size 2 were observed in the north of the region. Two of of the larger avalanches possibly stepped-down to the mid-March persistent weakness on north facing alpine slopes. Also reported were several loose sluffs to Size 1.5 in response to sun-exposure on south aspects.

Snowpack Summary

Another 10-20 cm of low density storm snow adds to the 30 cm of recent moist snow capped by a thin crust, that overlies a rain crust buried last Saturday. Reports suggest this crust exists up to about 2100m. West through southwesterly winds have shifted these new accumulations into touchy wind slabs in exposed terrain. A facet/crust persistent weakness buried mid-March is down approximately 50-100 cm and recently produced moderate sudden results in snowpack tests where it was found down 55 cm near the Duffey Lake Road. This remains the chief concern amongst avalanche professionals in the region due to it's potential for very large avalanches.

Problems

Persistent Slabs

There's some uncertainty as to how the deeply buried weak layers have responded to recent storms. A cautious approach is still required as avalanches failing at this interface may not be survivable.

Choose well supported terrain without convexities.>Avoid exposure to overhead avalanche terrain, large avalanches may reach the end of run out zones.>Resist venturing out into complex terrain, even if you observe no obvious signs of unstable snow.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

3 - 5

Storm Slabs

Recent storm accumulations have been shifted into deeper deposits by west through southwest winds. Watch for increased reactivity in exposed lee terrain.

Stay off recent wind loaded areas until the slope has had a chance to stabilize.>Be alert to conditions that change with elevation.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Valid until: Apr 2nd, 2015 2:00PM