Archived

Avalanche Forecast

Apr 5th, 2012–Apr 6th, 2012

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 Coastal.

Confidence

Good

Weather Forecast

A ridge of high pressure is expected to keep the northwest ranges mainly sunny and dry with light winds throughout the forecast period. Freezing levels are expected to reach 1500m during the day, but drop back down to sea level at night.

Avalanche Summary

Reports from Wednesday include wet loose avalanche activity up to Size 2.0 in response to direct sun exposure. Cornices have also been failing over the past couple of days, some of which triggered wind slab avalanches up to Size 2 on the slope below. Large glide avalanche activity also continued on solar aspects.

Snowpack Summary

15-40cm of new snow is settling and faceting, and generally bonding well to the previous predominately crusty snow surface. However, sheltered shady slopes may be harbouring buried surface hoar and/or preserved old storm snow from last week, which isn't as stable. Not only will daytime warming and sun-exposure cause surface snow to lose cohesion and cornices to weaken, they will also increase settlement rates and decrease slab stability.

Avalanche Problems

Loose Wet

Steep sun-exposed slopes in the afternoon. Although generally slow moving and in extreme cliffy terrain, wet Loose avalanches can entrain significant mass and have dire consequences if terrain traps are in the runout.

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

Elevations: All elevations.

Likelihood: Likely - Very Likely

Expected Size: 1 - 3

Cornices

Large and weak cornices could easily start popping off with sun-exposure. Not only are they a hazard in themselves, but can also act as a heavy trigger for very large avalanches on the slope below.

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

Elevations: Alpine.

Likelihood: Possible - Likely

Expected Size: 1 - 4

Wind Slabs

Generally lurking below ridgecrests, behind terrain features, and in gullies. Thick fresh wind slabs are likely sensitive to human triggers and cornice falls, especially with warming and sun-exposure.

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

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 1 - 5