Avalanche Forecast

Issued: May 2nd, 2013 4:45PM

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

a.l. horton, Parks Canada

Jasper.

The mountains are waking up and a significant avalanche cycle is expected this weekend as temperatures peak into the 20's.

Summary

Weather Forecast

Friday will see cloudy mild conditions with alpine winds dropping to light. The freezing level may rise to 2500m on friday. On Saturday,

Snowpack Summary

The 40cm of snow that fell last week in the Icefields area has been blown into windslabs below easterly alpine ridgelines. Mild conditions are warming this new snow and it is becoming wet and is sliding on the buried crusts. Relatively warm overnight temperatures are limiting the development of a supportive crust.

Avalanche Summary

Several loose wet avalanches were reported along the Icefields Parkway on all aspects and well into the alpine. These avalanches have been involving last week's storm snow and have been running far (300 to 400 m) with little mass. Most are size 1 to 1.5 but a few are up to size 2.

Confidence

Timing or intensity of solar radiation is uncertain on Friday

Problems

Loose Wet

Warm temperatures and strong solar effect are creating loose wet avalanches with last weekend's storm snow that are picking up mass and traveling far.

Start and finish early before the surface crusts melt.Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 3

Wind Slabs

40cm of storm snow has fallen since Saturday. West and NW winds have moved this snow onto lee aspects. South facing aspects are particularly likely trigger areas where the bonding of the new snow to the old melt freeze crust is weakest.

Be cautious as you transition into wind affected terrain.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Cornices

Large cornices are looming. On failure, deep releases may run far into the valley bottom.

Cornices become weak with daytime heating, so travel early on exposed slopes.Extra caution needed around cornices with current conditions.

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

2 - 3

Valid until: May 3rd, 2013 4:45PM