Avalanche Forecast

Issued: Apr 14th, 2018 4:00PM

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

deryl kelly, Parks Canada

Jasper.

Snow continues overnight and through the day Sunday. Best riding is on sheltered areas at Treeline. Avoid traveling or stopping under large slopes or corniced features as they may be sensitive to triggering.

Summary

Weather Forecast

Scattered and localized flurries will continue overnight and through the day Sunday. Accumulations may be as much as 4cm overnight and a further 10cm over the day. At lower elevations (under 2200m) expect wet flurries or rain in the afternoon. Winds are expected to shift to the east, remaining light with moderate gusts at ridge top.

Snowpack Summary

14cm HST overnight, with varied localized amounts as unsettled weather continues. Moderate SW winds have certainly overloaded wind slabs and cornices in open areas in the ALP. Persistent instabilities (down 40 to 100 cm) are already sensitive to large triggers like cornices, especially on N asp slopes at TL and ALP elevations.

Avalanche Summary

Road patrols in Maligne and Icefields regions. Very little natural slab activity seen in both regions. It was noted that cornices look huge. Numerous small loose wet slides observed at low elevations and solar asp, up to 2500m. Great information being shared daily on Avalanche Canada's MIN Reports for the Maligne, Whistler's Creek and Ice regions.Â

Confidence

Intensity of incoming weather systems is uncertain on Sunday

Problems

Wind Slabs

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

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

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Persistent Slabs

A slab up to 1m thick overlies: weak faceted crystals (well developed in shallow areas), surface hoar (at, and just above treeline), and sun crusts (on steep S and W aspects). Faceting has reduced slab strength below treeline and in shallow areas.

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

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

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 3

Cornices

Large cornices noted in all areas of the bulletin region.

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

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1.5 - 3

Valid until: Apr 15th, 2018 4:00PM