Avalanche Forecast

Issued: Apr 9th, 2019 4:00PM

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

jonas hoke, Parks Canada

Jasper.

Several parties have been surprised by dramatic whumphs on north facing fans below large terrain features recently. Evaluate the snowpack carefully before committing to any big lines.

Summary

Weather Forecast

Unsettled air pushed inland from a low pressure systems hitting the north coast will give several waves of snow flurries, with up to 15cm of accumulation by the end of the week. Wednesday: Cloudy with sunny periods. Afternoon flurries (up to 5cm). Treeline temps: Low -8 C. High -2 C. Ridge wind light SW. Freezing level: 2100m.

Snowpack Summary

Incoming new snow will be covering a strong surface crust on all aspects below treeline, and in to the alpine on solar aspects. A winter snowpack remains on N aspects treeline and above, with small pockets of windslab in lees, facets under an 20-50cm slab in isolated areas, and a weak base of facets and depth hoar in shallow snowpack areas.

Avalanche Summary

No new activity has been observed or reported.

Confidence

Forecast snowfall amounts are uncertain

Problems

Wind Slabs

Pockets of windslab in immediate lees will be buried by incoming new snow, making them more difficult to manage.

Be careful with wind loaded pockets, especially near ridge crests and roll-overs.

Aspects: North, North East, East.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 1.5

Persistent Slabs

Evidence from recent snowpack tests and whumphing would suggest that a weak layer of facets persists down 20-50cm in some areas, and may be becoming reactive with incremental loading from recent small snowfalls.

Whumpfing, shooting cracks and recent avalanches are all strong inicators of unstable snowpack.Carefully evaluate big terrain features by digging and testing on adjacent, safe slopes.

Aspects: North, North East, East.

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

1.5 - 2.5

Valid until: Apr 10th, 2019 4:00PM