Avalanche Forecast

Issued: Nov 21st, 2020 4:00PM

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

Benjamin Firth,

Jasper.

Avoid areas that have been wind loaded and watch for rocks/fallen trees that might lurk just below the surface. Public field reports can be submitted through the MIN and are much appreciated

Summary

Weather Forecast

Tonight: Mainly cloudy. Precip: Nil. Alpine temps: Low -10 C. Ridge wind SW: 15 km/h. Freezing level at valley bottom.

Sunday: Isolated flurries. Precip: Trace. Alpine temp: High -8 C. Ridge wind SW: 15-30 km/h. Freezing level at valley bottom.

Monday: Isolated flurries. Precip: Trace. Alpine temp: Low -9 C, High -7 C. Ridge wind SW: 10-30 km/h.

Snowpack Summary

Up to 45cm of new snow over the past 72 hours .The snowpack is ~100cm at treeline. The Nov. 4th rain crust up to 2600m depending on location, and is up to 70cm deep. Continued wind slab development on N and E aspects ridgetop down into treeline.

Avalanche Summary

Several natural wind slab avalanches in the alpine on north aspects have been observed in the Jasper and Bald hills region over the past 48 hours. No field trips today, limited observations

Confidence

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

Problems

Wind Slabs

Up to 45cm of new snow with moderate winds at ridge top has produced windslabs in the immediate lee at ridge tops and down into tree line.

Be careful with wind loaded pockets while approaching and climbing ice routes.
Use caution in lee areas. Recent wind loading have created wind slabs.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Persistent Slabs

Pockets of previous wind deposited snow overlies the Nov 4 rain crust and continues to be reactive to skier traffic and large loads such as explosives.

Pockets of persistent slabs linger on alpine lee features.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2.5

Valid until: Nov 22nd, 2020 4:00PM