Avalanche Forecast

Issued: Apr 19th, 2012 10:17AM

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

mbender, Avalanche Canada

Sea To Sky.

Summary

Confidence

Fair - Intensity of incoming weather is uncertain on Friday

Weather Forecast

FRIDAY: Thursday night into Friday may have brought 10-15cm of precipitation. Light to moderate precipitation in the early part of the day on Friday. Strong southwesterly winds and a freezing level of 1300m. SATURDAY: A ridge of high pressure brings mainly dry conditions and warmer temperatures. Winds light southwesterly and freezing levels up to 2000m. SUNDAY: The high pressure prevails but freezing levels rise to 2500m.

Avalanche Summary

Recent observations include cornice falls (size 1-2). Loose moist avalanches have been observed during periods of warming along with thin windslabs (10-20cm deep) above releasing to size 1.

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 may continue to 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

Expected Size

1 - 2

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 - 4

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 - 5

Valid until: Apr 20th, 2012 9:00AM