Avalanche Forecast

Issued: Jan 13th, 2019 4:47PM

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

pgoddard, Avalanche Canada

Sea To Sky.

Spring weather and a winter snowpack makes for a power struggle. Dial back your exposure to steep terrain and cornices until temperatures drop.

Summary

Confidence

Moderate - Freezing levels are uncertain on Monday

Weather Forecast

MONDAY: Sunny and warm. Freezing level near 2700 m. Alpine high near +7. Light winds. TUESDAY: Sunny and warm. Freezing level near 1800 m. Alpine high near 0. Light winds. WEDNESDAY: Mix of sun and cloud. Freezing level near 1600 m. Alpine high near -1. Light winds. More details can be found in the Mountain Weather Forecast.

Avalanche Summary

Several large cornice falls were triggered naturally and with explosives on Saturday. Some of these triggered size 2 slabs on slopes below. There is a trend of cornice falls increasing in size and frequency as the warm weather continues. Loose wet avalanches to size 2 were also failing naturally on sunny aspects on Saturday.

Snowpack Summary

Warm temperatures are weakening surface snow layers and making cornices extra touchy. The warmth can also penetrate into more deeply buried weak layers. Minimal overnight freeze is expected, meaning warming is likely to affect the snowpack early in the day.Refrozen crusts may be found on all aspects below about 1800-2000 m; and on sunny aspects in the alpine in some places. These may break down through the day. Cold, dry and possibly wind-affected snow may still be found on various aspects in the alpine. Variable instabilities exist in recent storm snow layers. Two weak layers exist in the upper 2 m of the snowpack at and below treeline. These layers consist of surface hoar (feathery crystals) in more sheltered areas and a crust on solar aspects and on all aspects below 1600m.In the lower snowpack, a crust/facet (sugar snow) layer is now over 2 m deep. This layer may still be reactive to heavy loads (such as a cornice fall) in isolated areas.

Problems

Cornices

Large cornices have been dropping in many locations with the warm weather. Give them a wide berth at ridgetop and don't linger below them.

Minimize exposure to cornices overhead and stay well back on ridges.Be aware of what is above you at all times.Be aware of the potential for very large avalanches due to a deeply buried weak layer.

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

Elevations: Alpine.

Likelihood

Likely - Very Likely

Expected Size

1 - 3

Loose Wet

Sun and warm temperatures are causing loose wet and wet slab avalanche conditions. Look for clues like sticky snow, rollerballing or recent avalanche activity, that indicate the snowpack is losing strength.

Watch for terrain traps where small amounts of snow will acumulate into deep deposits.Minimize exposure to steep, sun exposed slopes when the solar radiation is strong.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

1 - 2

Valid until: Jan 14th, 2019 2:00PM