Avalanche Forecast

Issued: Apr 15th, 2018 4:00PM

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

deryl kelly, Parks Canada

Jasper.

Winter persists for the next 2 days. Avoid traveling or stopping under large slopes or corniced features as they may be sensitive to triggering.

Summary

Weather Forecast

Scattered flurries to continue for the next 48 hours. Accumulations and loading may vary significantly. Forecasted snow amounts for 25 cm for the Icefields and 20 for Maligne regions. At lower elevations (under 1800m) the snowpack is vanishing and what snow remains is not supportive with warming. Winds remain light with mod gusts at ridge top.

Snowpack Summary

A further 4cm, with previous HST totals up to 20cm with varied localized amounts as unsettled weather continues. Mod SW winds have certainly overloaded wind slabs and cornices in open areas at TL and ALP. Persistent instabilities (down 40 to 100 cm) are sensitive to large triggers like cornices, especially on N asp slopes at TL and ALP elevations.

Avalanche Summary

Poor visibility in the region today, reported audible (heard, not seen) avalanches in the Icefields.A large (Size 2.5) persistent slab avalanche was reported Saturday, from a N asp in the alpine.Great information being shared daily on Avalanche Canada's MIN Reports for the Maligne, Whistler's Creek and Icefields regions.

Confidence

Timing, track, or intensity of incoming weather system is uncertain

Problems

Wind Slabs

Overloaded and under tension, new and buried windslab in the Alpine and TL is sensitive to further loads, like more wind, more snow, more sun and, especially riders.

If triggered the wind slabs may step down to deeper facet layers resulting in larger avalanches.

Aspects: North, North East, East, South East, South.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Cornices

Large cornices in all areas of the bulletin region. These failures are triggering persistent instabilities and the subsequent avalanches are proving large and destructive. Give these features a lot of room.

Avoid travel on slopes that are exposed to cornices overhead.Minimize overhead exposure during periods of heavy loading from new snow, wind.

Aspects: North, North East, East, South East.

Elevations: Alpine.

Likelihood

Possible - Likely

Expected Size

1.5 - 2.5

Persistent Slabs

A slab up to 1m thick overlies: weak faceted crystals, and sun crusts (on steep S and W aspects). This problem has been associated with large triggers like cornices and the subsequent avalanches are proving large and destructive.

Minimize exposure to overhead avalanche terrain, large avalanches may reach run out zones.Carefully evaluate big terrain features by digging and testing on adjacent, safe slopes.

Aspects: North, North East, East, South East, South, South West.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1.5 - 3

Valid until: Apr 16th, 2018 4:00PM