Avalanche Forecast

Issued: Apr 15th, 2012 4:00PM

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

pgoddard, Avalanche Canada

Sea To Sky.

Summary

Confidence

Poor - Timing, track, or intensity of incoming weather is uncertain for the entire period

Weather Forecast

A series of frontal disturbances will affect the region over the next few days. The timing and intensity of these systems is uncertain. Freezing levels are also uncertain.Monday: Moderate precipitation. Moderate SW winds. Freezing level around 1600 m. Clearing in the evening.Tuesday: Sunshine in the morning, changing to cloud and light precipitation late in the day. Moderate S winds. Freezing level around 1400 m. Wednesday: Moderate precipitation. Moderate SW winds. Freezing level around 1400 m.

Avalanche Summary

Recent observations include cornice falls (size 1-2) and glide slab releases to size 3.5. Loose moist avalanches have been observed during periods of warming.

Snowpack Summary

A generally strong and deep spring snowpack exists. At this time of year, snowpack stability tends to decrease during times of warming (e.g. on slopes receiving sunshine, during rainfall, in the afternoon and at low elevations) and improve when the surface freezes. Conditions may be quite icy in the morning. A crust layer from late March, buried within the upper 2 m of the snowpack, remains a lingering concern, although the snowpack above it is settling and strengthening. Large cornices threaten slopes and glide slab releases are a possibility, especially in steep rocky terrain.

Problems

Wind Slabs

Wind slabs may develop with incoming snow and wind. Be alert for these behind ridges and terrain breaks.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 4

Loose Wet

Wet loose or slab avalanches are most likely at times when temperatures are warm, e.g. on slopes receiving sunshine, during rainfall, in the afternoon and at low elevations. Avoid exposure to slopes which are sporting glide cracks.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 6

Cornices

Large cornices are looming. These are a hazard in themselves and could trigger avalanches on the slope below.

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 4

Valid until: Apr 16th, 2012 9:00AM