Avalanche Forecast

Issued: Mar 30th, 2017 4:19PM

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

triley, Avalanche Canada

Lizard-Flathead.

The quick change from stormy weather to clear sunny skies with high freezing levels is a concern for natural avalanches. This is not the time for big objectives.

Summary

Confidence

Moderate - Forecast snowfall amounts are uncertain on Friday

Weather Forecast

Overnight: 5-10 cm of new snow with freezing down to 1300 metres by morning. Friday: Clearing in the morning, with strong solar in the afternoon. Daytime freezing rising up to 2200 metres with light southwest winds. Saturday: Little or no re-freeze below 2200 metres. Mix of sun and cloud with flurries developing in the afternoon. Sunday: Overcast with light snow and light winds. Daytime freezing levels around 1800 metres.

Avalanche Summary

Numerous storm slab and loose wet avalanches were reported from the Fernie area on Thursday. One natural cornice fall was size 3.0, and pulled a storm slab from the slope below. Our uncertainty revolves around whether the snowpack will get a chance to re-freeze in the morning before the sun starts to heat the snowpack. I think there is a good chance that storm slabs will continue to be reactive, and strong solar may release cornices and storm slabs as daytime temperatures and freezing levels climb.

Snowpack Summary

Storm slabs continue to grow at higher elevations. Another 10-15 cm by Thursday morning has made the recent storm total near Fernie 50-70 cm. In the Corbin area, there was a total of 25cm on Wednesday. Storm snow is not bonding well to crusts in the alpine and at treeline. Below 1800 metres the snow is moist or wet. The recent storm snow may be sitting on a crust that developed just before the new snow arrived. This crust may act as a smooth sliding surface when the sun heats the storm slab. Deeply buried facets may spring to life due to the added load of the storm slabs, and the possibility of strong solar radiation over the next couple of days.

Problems

Storm Slabs

Storm slabs continue to develop in the alpine and at treeline. These slabs have been very reactive over the past few days. Forecast sun and high freezing levels may result in easy triggering or natural releases.

The new snow will require several days to settle and stabilize.Minimize exposure to steep, sun exposed slopes when the solar radiation is strong.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely - Very Likely

Expected Size

1 - 3

Loose Wet

Watch out for wet snow at lower elevations or on sunny slopes if the sun comes out during the day.

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

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Likely

Expected Size

1 - 3

Cornices

New cornice growth may fall off naturally when the sun comes out and the freezing levels rise.

Pay attention to overhead hazards like cornices which could easily trigger deep slabs.Do not travel on slopes that are exposed to cornices overhead.

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

Elevations: Alpine.

Likelihood

Likely - Very Likely

Expected Size

2 - 3

Valid until: Mar 31st, 2017 2:00PM