Avalanche Forecast

Issued: Apr 13th, 2015 8:00AM

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

Lydia Marmont, Parks Canada

Glacier.

A complex winter snowpack persists at Treeline and above. Snowpack tests indicate a weak layer down 65 cm to be easy to skier trigger. Watch and listen for whumphing, cracking and recent avalanches and remain conservative with terrain choices.

Summary

Weather Forecast

Mainly cloudy today with isolated flurries and moderate to strong south winds at ridgetop. Freezing levels will be higher today, rising to 1900m. Another 5 - 10 cm of snow expected tonight and Tuesday then drying out over the week with a mix of sun and clouds and freezing levels around 2000m.

Snowpack Summary

Up to 40cm of recent storm snow over the past three days. The storm layer sits on a crust on solar aspects and surface hoar on sheltered N aspects. Yesterday a profile at 2000m on a north aspect showed a very weak layer down 65cm. This layer produced easy to moderate sudden shears failing on a crust.

Avalanche Summary

Numerous Na Sz 1.5 to 2.5 Natural avalanches observed yesterday on North and south aspects. `

Confidence

Due to the number of field observations

Problems

Storm Slabs

40cm of recent storm snow sits over surface hoar on northerly aspects. Associated winds with the storms have been enough to create slabs in exposed areas. Its time to select more conservative terrain.

Watch for whumpfing, hollow sounds, shooting cracks or recent avalanches.If triggered the storm/wind slabs may step down to deeper layers resulting in large avalanches.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Persistent Slabs

A weak layer down 65 cm was producing easy sudden shears yesterday, failing on 4F snow between a crust and a more dense layer. Whumphing and cracking was observed and was suspected to be caused by failure at this layer.

Whumpfing is direct evidence of a buried instability.Watch for whumpfing, hollow sounds, shooting cracks or recent avalanches.