Archived

Avalanche Forecast

Apr 20th, 2014–Apr 21st, 2014

Alpine

3: Considerable

The avalanche danger rating in the alpine will be considerable

Treeline

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

2: Moderate

The avalanche danger rating below treeline will be moderate

Alpine

2: Moderate

The avalanche danger rating in the alpine will be moderate

Treeline

2: Moderate

The avalanche danger rating at treeline will be moderate

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

Regions: Glacier.

Tempting powder lines on North aspects today have the potential to fail as a slab avalanche. Test slopes before committing to your ski down. If the sun comes out this afternoon, be cautious if it starts to destabilize the snow surface.

Weather Forecast

A weak ridge of high pressure is expected to move into the interior today. Light precip this morning will give way to sun and cloud this afternoon. Freezing levels will rise to around 1800m with moderate southerly winds. Tomorrow freezing levels about 1600m with light precip. On Tuesday moderate snowfall with mod to strong winds is possible.

Snowpack Summary

20-30cm of HST overlies a crust. Deeper pockets of wind slab formed below ridge crests and on lee features from Southerly winds. Dry snow will be found on due N aspects and on other aspects above 1500m, this could change today with rising temperatures. Several crusts exist in the top meter of the snowpack. Isothermal snow developing on solar asp.

Avalanche Summary

Yesterday a cornice broke off a N aspect and triggered a size 2.0 slab avalanche which failed in the HST over a crust. Four other slides were observed, size 2.0-2.5. Most were loose moist, but one was a dry slab avalanche on a North asp. On due N aspects a field team was easily able to ski cut 10cm of HST over a crust which propagated as a slab.

Confidence

Intensity of incoming weather systems is uncertain on Tuesday

Avalanche Problems

Storm Slabs

20-30cm of HST lies over a crust. There will be pockets of triggerable wind slab below ridge crests and lee features in the alpine and at tree line. The HST may be possible to fail as a moist slab below tree line in steeper terrain.

Use caution in lee areas. Recent wind loading have created wind slabs.If triggered the storm slabs may step down to deeper layers resulting in large avalanches.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Possible

Expected Size: 1 - 3

Loose Wet

If the sun come out this afternoon, caution on solar aspects and at lower elevations where the snowpack is becoming isothermal.

Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 1 - 3

Cornices

If a cornice fails today, there is a likely chance it will trigger the recent HST and possibly deeper weak layers in the snowpack.

Give cornices a wide berth when travelling on or below ridges.Cornices become weak with daytime heating, so travel early on exposed slopes.

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

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 2 - 4