Archived

Avalanche Forecast

Mar 30th, 2014–Mar 31st, 2014

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.

Prolonged sun exposure may initiate natural avalanche activity, especially on south through west facing slopes.

Confidence

Fair - Timing or intensity of solar radiation is uncertain

Weather Forecast

Synopsis: A ridge of high pressure over the NWT continues to advance south. Looks like continued cool and dry conditions for the NW for the forecast period. The models show an organized system that approaches the north coast Wednesday/Thursday, check back tomorrow for more details. Monday: Freezing Level: 800 - 1300m; Precipitation: Nil; Wind: Treeline: Light, NW | Ridgetop: Light, NWTuesday: Freezing Level: 600 - 1300m Precipitation: Nil; Wind: Treeline: Light, SW | Ridgetop: Moderate, WWednesday: Freezing Level: 400m - 1300m; Precipitation: Trace; Wind: Treeline: Light, S | Ridgetop: Moderate, SW

Avalanche Summary

No avalanche observations from Saturday.On Friday loose snow was sluffing to size 1, several sluffs initiated thin size 1 slabs running on an old suncrust. There was a second hand report of a skier triggered size 2 avalanche at treeline that resulted in the skier going for a ride. Sounds like everyone made it out okay, and that the folks involved will head back later in the spring to find their lost gear. If you were part of this incident, we'd love it if you'd fill out a report. Thanks!

Snowpack Summary

Strong Easterly winds have been reported to have caused intense wind transport of the recent storm snow, developing pockets of wind slab on various aspects in the alpine and at treeline. Forecast cool temperatures are not expected to promote much settling or bonding of the near surface layers, and probably not much change to the persistent weak layers. The deeply buried persistent weak layers continue to provide moderate to hard sudden planar results in snow profile tests, but may be deep enough to require a heavy load for triggering. The March weak layer is a combination of hard wind-scoured slab surfaces in exposed terrain, facets and/or surface hoar in sheltered and north aspects, and sun crust on steep solar aspects. This layer is widespread throughout the forecast region and is now buried close to 150cm in most parts of the area. A late January/early February crust/facet/surface hoar combo is now buried 200 cm or more.

Avalanche Problems

Wind Slabs

Strong winds have created isolated pencil hard wind slabs 20 - 50 cm in depth at and above treeline. Where new snow is available for transport, soft slabs may be found too.

Use ridges or ribs to avoid pockets of wind loaded snow.>Watch for areas of hard wind slab on alpine features.>Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.>

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

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 2 - 4

Deep Persistent Slabs

At this point the deep persistent weak layers would likely require a specific trigger like cornice fall, a surface avalanche in motion, or a rider finding the sweet spot, to be activated.

Be aware of the potential for large, deep avalanches due to the presence of buried weak layers.>Avoid convexities or areas with a thin or variable snowpack.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Unlikely - Possible

Expected Size: 3 - 6