Archived

Avalanche Forecast

Jan 23rd, 2014–Jan 24th, 2014

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

Alpine

2: Moderate

The avalanche danger rating in the alpine will be moderate

Treeline

1: Low

The avalanche danger rating at treeline will be low

Below Treeline

1: Low

The avalanche danger rating below treeline will be low

Regions: Northwest Inland.

Confidence

Fair - Due to the number of field observations

Weather Forecast

Friday: A mix of sun and cloud, with valley fog likely. Light winds. Freezing level reaching 1600m with alpine temperatures close to +5 C, but cooler in valley bottoms. Saturday: Sunny with cloudy periods, with valley fog likely. Light winds. Freezing level reaching 3500m with alpine temperatures close to +10 C, but cooler in valley bottoms. Sunday: A mix of sun and cloud, with valley fog likely. Light winds. Freezing level lowering to 1000m and a temperature inversion maintaining cooler temperatures in valley bottoms.

Avalanche Summary

Recent reports include a Size 2 natural storm slab avalanche that ran on a buried crust on NE aspect at 900m, and a Size 3 natural glide avalanche. Wet loose snow avalanches are likely, especially on sun-exposed slopes in the afternoon.

Snowpack Summary

The surface snow is likely undergoing melt-freeze cycles particularly on all but high elevation shady aspects. Approximately 5 to 25cm (elevation and drainage dependant) of recent storm snow sits on various old snow surfaces including crusts. Previously strong winds have resulted in highly variable snowpack depths in exposed areas with deep drifts, scoured areas, and sastrugi.Â The surface hoar persistent weakness buried early January is most prevalent down approximately 50cm on sheltered slopes at treeline. Professionals continue to keep an eye on the basal facets which can be found down near the ground.

Avalanche Problems

Loose Wet

Generally small, slow, and often limited to extreme cliffy terrain; however, these dense avalanches can easily knock you off your feet and take you for a ride.

Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.>Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.>

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

Elevations: Alpine, Treeline.

Likelihood: Likely

Expected Size: 1 - 3

Deep Persistent Slabs

Basal facets, buried surface hoar, and glide avalanches are all expected to become more sensitive to triggering with warm temperatures and solar radiation. Although tricky to pinpoint when and where they might occur, the consequences could be severe.

Be aware of the potential for large, deep avalanches.>Avoid open slopes and convex rolls at and below treeline where buried surface hoar may be preserved.>Avoid convexities or areas with a thin, rocky or variable snowpack.>Avoid slopes with glide cracks.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Unlikely - Possible

Expected Size: 4 - 7

Wind Slabs

Although becoming stubborn, isolated wind slabs below ridge crests may still be sensitive to human triggers.

Start on small terrain and slope-cut the top of slopes before riding them.>Highmark or enter your line well below ridge crests to avoid wind loaded pillows.>Be cautious as you transition into wind affected terrain.>

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

Elevations: Alpine, Treeline.

Likelihood: Unlikely - Possible

Expected Size: 1 - 3