Avalanche Forecast

Issued: Apr 19th, 2012 10:17AM

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

Avalanche Canada mbender, Avalanche Canada

Summary

Confidence

Fair - Due to limited field observations for the entire period

Weather Forecast

FRIDAY: Light to moderate precipitation in the early part of the day. Thursday night into Friday may have brought 10-15cm of precipitation. 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

Spring conditions exist in the region. Exposure to the sun, warm temperatures, and periods of rain are the most likely factors to influence the avalanche danger. If the temperatures go below freezing overnight, strong crusts should develop that are likely to hold the snowpack together. If the sun shines for a few hours, the crusts may break down quickly and moist surface snow avalanches may start running naturally. Continued warming from more sun, rain, or no overnight freeze, may cause surface avalanches to step down and trigger deeper wet slab avalanches. Prolonged warming may cause very deep releases on weak layers that were deposited early in the season, or on depth hoar that developed during the winter. It is important to monitor the temperature and the freezing levels as they may change rapidly from day to day.

Snowpack Summary

As we transition into spring the surface layers have a great deal of influence on the snowpack. When there is a solid re-frozen surface crust, travel is fast and easy, and the snowpack is held together by the surface cap. Any deeper persistent weak layers are unlikely to fail until the surface cap breaks down from daytime heating. When there is no crust, any deeper weak layers may fail depending on the amount of heat and the triggering force that is applied. If it cools off and snows, new snow and windslabs may not bond well to the hard spring crusts.

Problems

Cornices

An icon showing Cornices
Large cornices are looming. A cornice fall can act as a heavy trigger for avalanches on the slope below.

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 5

Wind Slabs

An icon showing 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

Expected Size

1 - 3

Loose Wet

An icon showing Loose Wet
Wet loose avalanches are most likely on steep slopes 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 - 3

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