Archived

Avalanche Forecast

Apr 19th, 2015–Apr 20th, 2015

Alpine

3: Considerable

The avalanche danger rating in the alpine will be considerable

Treeline

3: Considerable

The avalanche danger rating at treeline will be considerable

Below Treeline

2: Moderate

The avalanche danger rating below treeline will be moderate

Alpine

3: Considerable

The avalanche danger rating in the alpine will be considerable

Treeline

3: Considerable

The avalanche danger rating at treeline will be considerable

Below Treeline

2: Moderate

The avalanche danger rating below treeline will be moderate

Alpine

4: High

The avalanche danger rating in the alpine will be high

Treeline

4: High

The avalanche danger rating at treeline will be high

Below Treeline

3: Considerable

The avalanche danger rating below treeline will be considerable

Regions: Glacier.

Increasing hazard as the day progresses with the solar radiation. Strong daytime warming will make triggering instabilities in the snowpack more likely. Limit your groups exposure to the overhead cornice hazard.

Weather Forecast

High pressure ridge over the the Province will keep the skies clear for today and tomorrow. Freezing levels are forecast to rise to ~2400m, dropping tonight and then rising to 2700m for tomorrow. Alpine winds are forecast to remain light from the west. No precipitation is expected until Wednesday.

Snowpack Summary

Overnight refreeze created a surface crust over moist or wet snow. The snowpack on solar aspects is mostly moist and composed of multiple crusts. This will differ on sheltered north aspects in the alpine where dry snow can still be found. Weak layers still exist in the upper snowpack on crusts or surface hoar on north aspects higher up.

Avalanche Summary

Yesterday, backcountry report of a small cornice triggering an avalanche on Bruins Ridge, size 2.5, E aspect, 100m wide, 30cm deep, 250m long which ran into Hospital Bowl. Reports of lots of whumphing in Connaught. Several avalanches to size 2.0 in the highway corridor. Size 2.0 glide crack avalanche in the highway corridor on Mt Tupper 2 days ago.

Confidence

Avalanche Problems

Persistent Slabs

Weak layers are down 30-60cm. Surface hoar on northerly aspects and a sun crust on south aspects. Daytime warming, loose avalanches and skiers can trigger this layer. Lots of whumphing was reported in the Connaught drainage yesterday.

Whumpfing, shooting cracks and recent avalanches are all strong inicators of unstable snowpack.Be careful with wind loaded pockets, especially near ridge crests and roll-overs.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 1 - 3

Loose Wet

Strong solar radiation will have an effect on the sunny aspects today. Loose avalanches can get surprisingly large once they get going. A good plan is to stay off of large slopes that are in sun by later this morning.

Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.Watch for clues, like sluffing off of cliffs, that the snowpack is warming up.

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

Elevations: All elevations.

Likelihood: Likely

Expected Size: 1 - 3

Cornices

Large cornices have the potential to fall with the addition of sun and warming. Remember that cornices above shaded slopes are being warmed from behind by the sun. Cornices will be most dangerous during the height of daytime warming in the afternoon.

Cornices become weak with daytime heating, so travel early on exposed slopes.

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

Elevations: Alpine.

Likelihood: Possible

Expected Size: 2 - 3