Avalanche Forecast

Issued: Apr 18th, 2013 8:00AM

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

jon schleiss, Parks Canada

Glacier.

In wind affected areas at treeline and in the alpine expect windslabs that are rider triggerable. The winter permit system is no longer in effect.

Summary

Weather Forecast

Sunny with cloudy periods and the possibility of snow flurries for today with Light to moderate precipitation for Friday and Saturday and clearing again on Sunday. Freezing levels are expected to rise to2100m today, and 1900m for Friday and Saturday.

Snowpack Summary

At treeline there is 40-50cm of settling storm snow over the April 3rd crust which varies in thickness due to strong winds at tree line and alpine elevations. Below this crust in most areas the snowpack is isothermal.

Avalanche Summary

Early this week, there was a Skier Accidental, size 3.0 on the east face of Mt Swanzy, depth 100cm, 150m wide, suspect April 3 crust. Skiers were not involved, and later the same day a Skier Accidental, size 2.0, Forever Young couloir, depth 30cm, 40m wide ran to 2/3 fan. Skier got taken down onto the fan before he managed to self arrest.

Confidence

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

Problems

Wind Slabs

Winds over the last week have been strong and have caused wind slabs on all aspects at treeline and in the alpine. On solar aspects this interface may be poorly bonded where surface hoar had formed on buried sun and temperature crusts.

Dig down to find and test weak layers before committing to a line.Watch for areas of hard wind slab in steep alpine features.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

2 - 3

Loose Wet

Some clear skies and freezing levels rising to 2100m today will increase the avalanche hazard on sun affected slopes. Pay attention to overhead cornice hazard, as cornices are weak and may be getting heated by the sun above.

Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.Cornices become weak with daytime heating.

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

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 2

Persistent Slabs

Large avalanches are still being human triggered as was demonstrated Monday occurring on deeper instabilities. Small surface avalanches may trigger these deeper persistent slabs.

Sluffs may trigger deeper instabilities.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely

Expected Size

2 - 3

Valid until: Apr 19th, 2013 8:00AM