Avalanche Forecast

Issued: Nov 25th, 2012 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.

max darrah, Parks Canada

Jasper.

The storm snow appears to be bonding well and stability is improving, but wind slabs may still be triggered by light loads in specific terrain features.

Summary

Weather Forecast

Partly cloudy with isolated light flurries for the next couple of days. Predominantly light SW winds and temps in the -5 to -10 range. Potential for 5-10cm on Wednesday.

Snowpack Summary

Between 50 and 70cm of new snow since Nov 19 in the CIA. This new snow appears to be bonding well and has been subjected to relatively light winds (at TL), mainly SW. Lots of snow available for transport. May be approaching critical load on Nov crusts.

Avalanche Summary

Several Na and Xe yesterday at Marmot Basin in the 2-2.5 range, NE aspects above 2400m. Isolated Na activity in the CIA, cross loaded features at TL. No activity on the Nov crusts, all observed avalanches were in the top 50cm and involved WSL.

Confidence

Due to the number of field observations

Problems

Wind Slabs

Natural avalanches are being reported involving the top 10-30cm of the snowpack, suggesting that new wind slabs are touchy in wind loaded areas, particularly in the alpine.

Avoid ice climbs that are in terrain traps below large start zones.Avoid lee and cross-loaded terrain near ridge crests.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Persistent Slabs

Previous wind slabs can be found buried beneath the recent storm snow in exposed terrain. The increased load on these slabs from the recent snowfall may increase their likelihood of triggering.

The recent snow may now be hiding windslabs that were easily visible before the snow fell.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

2 - 3

Valid until: Nov 26th, 2012 4:00PM