Archived

Avalanche Forecast

Apr 14th, 2013–Apr 15th, 2013

Alpine

3: Considerable

The avalanche danger rating in the alpine will be considerable

Treeline

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

1: Low

The avalanche danger rating below treeline will be low

Alpine

2: Moderate

The avalanche danger rating in the alpine will be moderate

Treeline

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

1: Low

The avalanche danger rating below treeline will be low

Alpine

2: Moderate

The avalanche danger rating in the alpine will be moderate

Treeline

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

1: Low

The avalanche danger rating below treeline will be low

Regions: Northwest Inland.

There is limited information from the region, so this forecast is based primarily on remote telemetry and weather forecasts.

Confidence

Poor - Due to limited field observations

Weather Forecast

Monday: Expect mostly clear skies with alpine temperatures reaching -8 and freezing levels climbing to 1000m. Winds should be light from the east. There is a chance of clouds and convective snowshowers late in the day.Tuesday: Skies should be clear in the morning, with clouds building through the day. Alpine temperatures and freezing levels should reach -6 and 1100m. Light snow may begin late in the day as winds turn southerly.Wednesday: Expect mostly cloudy skies, with intermittent light snowfall. Temperatures should be around -6 with light to moderate southwest winds.

Avalanche Summary

Isolated reports of natural and rider triggered avalanches to size 1.5; slabs on east aspects and loose sluffs on south aspects.

Snowpack Summary

15-35cm of recent snow is generally bonding well to the previous snow surface, which includes crusts, facets and/or surface hoar (very isolated locations). Warm afternoon temperatures have moistened the surface snow on all but the highest and most sheltered slopes. Previous strong westerly winds created widespread hard and soft wind slabs in exposed areas and these slabs are now lightly buried. They have become stubborn to react to human triggers but may still be triggered by large loads such as a cornice fall. Below treeline, the surface snow is undergoing daily melt-freeze cycles with the upper meter of snow becoming wet and losing cohesion by mid-afternoon. Concerns remain for a patchy persistent weakness buried a month ago, and deeper in the snowpack, basal facets may become a concern with continued mild temperatures. Cornices are well-developed and have grown with the recent isolated storms.

Avalanche Problems

Wind Slabs

Variable winds have built windslabs in unusual locations. They are susceptible to human triggering in steep and/or convex terrain.

Be cautious as you transition into wind affected terrain.>Be aware of areas that have been reverse loaded by winds.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 1 - 4

Loose Wet

Surface snow on South and West slopes will destabilize if the sun comes out.

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

Aspects: North, North East, East.

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

Expected Size: 1 - 3

Cornices

Cornices are large and become fragile with large temperature swings common in the spring.

Give cornices a wide berth when travelling on or below ridges.>

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

Elevations: Alpine.

Likelihood: Unlikely - Possible

Expected Size: 1 - 5