Avalanche Forecast

Issued: Mar 20th, 2014 4:00PM

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

a.l. horton, Parks Canada

Jasper.

The new snow will be enticing however forecasters have little confidence in this snowpack. Cautious route finding and conservative decision making are essential.

Summary

Weather Forecast

Flurries will continue into the weekend. Winds are expected to remain light and temperatures will be anything but spring like with lows dipping to -20 and only recovering to -5 during the day.

Snowpack Summary

5 to 15 cm of new snow fell on top of the 30 cm of settled storm snow we received last weekend. This snow has buried various surfaces including windslab. The Feb. 10th drought layer is now almost a meter deep in the snowpack. Basal facets are still lurking at the base of this snowpack.

Avalanche Summary

No new observations today in the Marmot area. Patrols in the past few days observed the debris from numerous large avalanches. These avalanches exhibited wide propagation, were primarily found in big East facing alpine terrain, and several were triggered by cornice fall.

Confidence

Due to the number and quality of field observations on Friday

Problems

Persistent Slabs

The "drought layer" (Feb 10) has been sensitive in the past week, contributing to numerous large avalanches. Pay particular attention to moraines at treeline and cross-loaded features in the alpine.

Be aware of thin areas that may propogate to deeper instabilites.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 3

Wind Slabs

Windslabs are forming in wind prone areas below lee ridgelines at treeline and above.

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, South, South West.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Storm Slabs

Another 15 cm of new snow fell on top of this past weekend's 35cm storm. Although this snow appears to be bonding well, caution is warranted in steep terrain. Test the storm snow interface prior to committing to your line.

If triggered the storm slabs may step down to deeper layers resulting in large avalanches.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Valid until: Mar 21st, 2014 4:00PM