Avalanche Forecast

Issued: Apr 8th, 2015 8:18AM

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.

Peter, Avalanche Canada

Sea To Sky.

Stick to higher shady slopes for the best snow, but keep the persistent slab problem in mind when choosing your line.

Summary

Confidence

Good

Weather Forecast

Thursday: Mainly sunny. The freezing level climbs to around 2000 m during the day and drops below 1500 m overnight. Winds are light and variable. Friday: Increasing cloud with snow possible late. 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 are moderate from the SW.

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

A couple of persistent weak layers are still present in the upper snowpack. These have not been reactive for a few days now, but intense spring sun or cornice falls could be enough to reawaken this problem.

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

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.

Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.>Minimize exposure to sun exposed slopes when the solar radiation is strong.>

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 9th, 2015 2:00PM