Avalanche Forecast

Issued: Feb 22nd, 2013 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 Storm Slabs.

garth lemke, Parks Canada

Jasper.

If we get more snow than is forecast, the danger rating will increase. Assess wind-loading patterns carefully.

Summary

Weather Forecast

Friday evening may bring 10-20cm (10mm water equivalency), possibly more with local influences but precipitation amounts are uncertain. There is more confidence in severe SW alpine winds with brisk winds at treeline. Front expected to dissipate Saturday a.m.. Saturday to Monday will have flurries and seasonal temperatures.

Snowpack Summary

Variable windslabs exist in the alpine and treeline locations. They are bonding well. Expect a short lived storm snow instablity to form with the current system. Weak facets dominate low elevations. Solid midpack bridges basal facets treeline and alpine.

Avalanche Summary

No Patrol Friday. Thursday's Marmot Basin Portal creek patrol revealed no new avalanches. No Patrol on Wednesday.

Confidence

Forecast snowfall amounts are uncertain on Saturday

Problems

Wind Slabs

Saturday's 20cm of snow has evolved into a variable windslab and appears to be bonding well. It sits on a variety of surfaces such as previously hard slab and sastrugi.

Assess start zones carefully and use safe travel techniques.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 3

Storm Slabs

With the potential of this new snow load and winds Friday evening, expect increase in activity until has had few days to stabilize.

The new snow will requires several days to settle and stabilize.Choose conservative lines and watch for clues of instability.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 3

Valid until: Feb 23rd, 2013 4:00PM