Avalanche Forecast

Issued: Apr 20th, 2014 9:11AM

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

esharp, Avalanche Canada

Cariboos.

At this time of year resist the urge to rely on danger ratings alone. Daytime warming or periods of sun can rapidly elevated danger ratings above what is forecast. Check out this blog post for more info on how to manage risk during the spring.

Summary

Confidence

Fair - Due to the number of field observations

Weather Forecast

Synopsis: A weak ridge of high pressure will shift eastwards as the next system moves in over the region Monday night with precipitation forecast for Tuesday and Wednesday.Tonight and Monday: Partly cloudy with a chance of flurries/ Moderate southerly winds / Freezing levels 2000Tuesday: Light Flurries starting later in the day (5-10cm) / Light to moderate westerly winds / Freezing levels 1800-2000m Wednesday: Flurries (10-15cm) / Light westerly winds / Freezing levels 1500 to 2000m

Avalanche Summary

At lower elevations and on solar aspects small to large loose wet avalanche continue to be triggered on steep slopes. Cornices collapses have been reported during periods of daytime warming. Occasionally these heavy triggers have caused large deep slab avalanches on the slopes below.

Snowpack Summary

10 to 25 cm of recent storms snow is rapidly settling and appears to be bonding well to a supportive crust that can be found on all aspects and elevations except for high elevation north-facing terrain. Soft winds slabs may be found in the immediate lee of ridges and ribs. A second melt-freeze crust buried at the beginning of April can be found down 40-55cm. This layer has been variably reactive in snowpack tests.Several persistent weak layers exist in the snowpack of the region:- The mid-March sun crust/surface hoar layer down 50-80cm and the early-March crust/facet/surface hoar layer down around 80-120cm seem to be inactive.- The mid-February crust/facet/surface hoar combo is typically down 150 - 200cm. Human triggered avalanches on this layer are unlikely. Larger triggers such as cornice fall, a smaller avalanche in motion or prolonged warming could wake this layer up, resulting in very large and destructive avalanches.

Problems

Loose Wet

Expect to see an increase in avalanche activity at lower elevations or on solar aspects if the sun comes out for extended periods of time.

Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 3

Wind Slabs

Wind slabs immediately lee of ridge crest may be sensitive to human triggering.

Be cautious as you transition into wind affected terrain.>Cornices become weak with daytime heating. >

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 3

Deep Persistent Slabs

The potential for very large deep slab avalanches needs to remain on your radar. Cornice fall, strong sun, warming temperatures or a surface avalanche in motion could act as triggers.

Be aware of the potential for very large, deep and destructive avalanches due to the presence of deeply buried persistent weak layers.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

4 - 7

Valid until: Apr 21st, 2014 2:00PM