Avalanche Forecast

Issued: Mar 18th, 2013 4:13PM

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

garth lemke, Parks Canada

Jasper.

Cold overnight temperatures will help am stability yet daytime heating and sun will increase the danger in the afternoons. The odd large cornice drop has been noted this past week.

Summary

Weather Forecast

Tuesday will be sun, freezing level to 1100m and likely higher with the sun's energy, and light SW treeline winds. Wednesday will have a warm front bringing small pulse of snow and potentially rain low elevations, freezing level 1700m and increasing SW winds. Thursday freezing level will drop, flurries, and light to moderate West winds.

Snowpack Summary

Surface soft slabs are forming mainly at exposed treeline locations and above yet are spotty. Saturday's strong North winds reverse loaded many slopes and now moderate Westerlies continue to move the snow. 90cm of snow fell since Wednesday. At treeline, soft slabs rest on a suncrust 80 cm deep in south facing terrain. Midpack is otherwise strong.

Avalanche Summary

Field patrol Parkers ridge N and S sides had no cracking or whumphing however the surface slab is evolving and spotty. No new naturals noted. Sunday's patrol a few size 2.5 storm slab avalanches ran on large planar alpine slopes. They initiated in lower start zones at 2500m. Numerous loose solar sluffs to size 2 noted mainly SW-NW aspects.

Confidence

Timing or intensity of solar radiation is uncertain on Tuesday

Problems

Storm Slabs

80-100cm cm has fallen since Wednesday with initially strong N winds that shifted to moderate Westerly. Slopes below ridgelines have a soft slab developing yet remains spotty. Many gullies were reverse loaded. Wind transport is occurring in alpine.

Be careful with wind loaded pockets Avoid travelling in areas that have been reverse loaded by winds.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Loose Dry

There remains unconsolidated storm snow on and above local ice climbs. It is is susceptible to solar, wind and human triggering forming loose snow avalanches of significant mass. Enough to knock climbers or skiers off their line.

Be cautious of sluffing in steep terrain.Finish ice climbs early in the day before the temperature rises.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 2

Valid until: Mar 19th, 2013 4:00PM