Avalanche Forecast

Issued: Apr 9th, 2015 9:21AM

The alpine rating is moderate, the treeline rating is low, and the below treeline rating is low. Known problems include Persistent Slabs, Loose Wet and Cornices.

bcorrigan, Avalanche Canada

Sea To Sky.

The best riding will be on high sheltered north aspects, but be mindful of the buried weak layers. Solar aspects may become active in the afternoon.

Summary

Confidence

Fair - Timing, track, or intensity of incoming weather system is uncertain

Weather Forecast

Friday: Increasing cloud with snow beginning late in the afternoon, with possibility of 15 to 20cm of accumulation. The freezing level lowers to 1500 m and winds increase to moderate or strong from the S-SW. Saturday: Cloudy with periods of snow. The freezing level continues downward to around 1000-1200 m and winds should be moderate from the SW. Sunday, cloudy periods and flurries. Freezing level around 1000m and light to moderate south winds.

Avalanche Summary

Recent reports include minor pinwheeling or loose wet sluffs in steep sun-exposed terrain. There is also the potential for cornice falls with daytime warming and intense spring sunshine.

Snowpack Summary

Older dry powder (up to 25 cm) can still be found on north facing or shady slopes above 1800-2000 m. Previous southwest winds may have blown dry snow into wind slabs in lee terrain. Expect an ongoing melt-freeze cycle on all sun-exposed slopes. A facet/crust layer buried in mid-March is down approximately 70-130 cm and is still producing hard but sudden results in snowpack tests. This remains a concern in the region due to it's potential to produce very large avalanches. Cornices are also a concern these days. A cornice failure may trigger a large destructive avalanche.

Problems

Persistent Slabs

There are two persistent weak layers still present in the upper snowpack. These haven't been reactive for a few days now, but intense spring sun, a wind slab or cornice failure could be enough to reawaken this problem.

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

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 5

Loose Wet

Expect loose wet slides on steep sun-exposed slopes during the afternoon.

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.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Cornices

Cornices are large and weak in some places, and could fail with daytime warming and solar radiation.

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

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 4

Valid until: Apr 10th, 2015 2:00PM