Avalanche Forecast

Issued: Apr 13th, 2018 9:00AM

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

VIAC Jesse Percival, VIAC

Summary

Confidence

Moderate - numerous weather scenarios and differing forecast outcomes.

Travel & Terrain Advice

Identify and choose terrain options that avoid areas with freshly wind loaded snow and cross loaded features. Caution when travelling either above or below cornices. Make careful and cautious terrain choices when rain on snow events occur, temperatures warm rapidly or during any appearance of the sun.

Avalanche Summary

No new natural avalanches reported.

Snowpack Summary

Snowpack Details

Surface: New snow, breakable crust and moist conditions all dependent on elevation. Upper: moist and wet snow. Mid: March 22 melt freeze crust can be found down from 90 to 135 centimeters. Lower: Well settled.

Past Weather

Strong south east wind and precipitation in the form of snowfall between 30 cm to 50 cm with temperatures and freezing level between 800 and 1200 meters. Thursday temperatures cooled with very little precipitation forming a breakable crust on all aspect and all elevations.

Weather Forecast

A deepening and strong low pressure will bring strong south south west wind, moderate to heavy snowfall and rising freezing levels and temperatures. Friday: 20 to 40 cm of snowfall 10 to 20 mm of rainfall. Temperatures 1 overnight rising to 6 mid day, winds moderate to strong south west . Freezing level rising to 1200 m mid day. Saturday: 5 to 10 cm of snowfall 5 to 25 mm of rainfall. Temperatures 1 overnight rising to 5 mid day, winds moderate south west. Freezing level rising to 1000 m mid day. Sunday: 5 to 10 cm of snowfall temperatures rising to 5 mid day, winds light north east. Freezing level rising to 1200 m mid day.

Problems

Wind Slabs

An icon showing Wind Slabs
Past Strong south east wind and forecast strong south west wind combined with moderate to heavy snow fall will deposit up to 100 cm of new snow on lee aspects. These hazardous avalanche problems are located predominately in the alpine and treeline on both western and eastern aspects. Expect these avalanche to be touchy to very touchy to human triggering and if triggered will propagate far and wide and produce large to very large avalanches.

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

Elevations: Alpine, Treeline.

Likelihood

Likely - Very Likely

Expected Size

2 - 3

Loose Wet

An icon showing Loose Wet
Past rain and forecast rain will unconsolidated the upper snow pack making it very touchy to human triggering. Found on all aspect and predominately at treeline and below, will if triggered start as a small avalanche but will gain mass becoming large and may have enough power to push a mountain traveler into or over terrain traps.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 2

Cornices

An icon showing Cornices
New snow and strong south south west wind will continue to contribute to cornice growth and frailty and during the forecast period will become sensitive to human triggering. If trigger these hazardous features could when failing and falling onto the slopes below, then trigger either a wind slab or loose wet avalanche. Found at ridge tops on all north aspects in predominately the alpine but also in isolated locations at treeline. These hazardous features will become very susceptible to triggering from light triggers such as mountain travelers and when triggered will be large to very large in size. Always provide a wide berth when travelling either above or below cornices.

Aspects: North, North East, East.

Elevations: Alpine, Treeline.

Likelihood

Very Likely

Expected Size

1 - 2

Valid until: Apr 15th, 2018 9:00AM