Archived

Avalanche Forecast

Apr 7th, 2015–Apr 8th, 2015

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

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

Regions: Northwest Coastal.

Sunshine are warmth are the primary drivers of avalanche hazard. Avoid large sun drenched slopes if the snow is getting moist or wet.

Confidence

Fair - Due to the number of field observations

Weather Forecast

Wednesday: Mainly sunny. The freezing level peaks near 1500 m. Ridge winds are light to moderate from the S-SW. Thursday: Increasing cloud with snow developing late. The freezing level is around 1300-1400 m. Winds increase to strong or extreme from the S-SW. Friday: Moderate snow. The freezing level is near 1000-1200 m and winds are strong from the south.

Avalanche Summary

On Monday there was a report of a size 2 skier triggered slab and a size 1.5 remotely triggered slab in the northern part of region. These were both from alpine terrain and appeared to fail on a buried surface hoar layer. In the same part of the region a size 3.5 cornice triggered slab was reported from steep unskiable terrain. This likely released on a weakness near the base of the snowpack. Besides these two slabs, the only other reports are of small loose wet sluffs from steep sunny slopes.

Snowpack Summary

Recent storm snow accumulations vary across the region, with the greatest amounts near the coast. The storm snow sits on a variety of old snow surfaces including a layer of surface hoar and facets buried on March 25th. This weakness, now down approximately 40 to 60cm has the potential for propagating over large areas. The problem seems more touchy in the northern part of the region, but has been reported throughout the northwest coastal area. The early March facet/crust persistent weakness is now down over a metre and produces hard, sudden planar results in snowpack tests.

Avalanche Problems

Loose Wet

Sunny skies and daytime warming could lead to loose wet surface sluffs on steep sunny slopes. Also, give cornices a wide berth.

Minimize exposure to sun exposed slopes when the solar radiation is strong.>Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.>Cornices become weak with daytime heating, so travel early on exposed slopes.>

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

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

Expected Size: 1 - 2

Persistent Slabs

The March 25th persistent weak layer is still on the radar and should be treated with respect. It could be triggered by a smaller wind slab or a loose wet avalanche, or by a rider in the wrong spot.

Be aware of the potential for large avalanches due to the presence of buried surface hoar.>Choose conservative lines and watch for clues of instability.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 1 - 4