Archived

Avalanche Forecast

Mar 12th, 2015–Mar 13th, 2015

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

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.

Conditions are changing. Warm temps, rain, snow and wind make for variable conditions and challenging decisions. It's time to carefully assess terrain choices and use good group management practices.

Weather Forecast

Precip should taper off this morning, and we may see some sunny breaks this afternoon. Alpine temps will remain around 0'C, with moderate gusting to strong S'ly winds forming new windslabs above treeline. Friday will warm with sunny periods, which may destabilize the new snow. On Sat a a warm windy storm arrives which may bring significant snow.

Snowpack Summary

Freezing levels are hovering around 1900m. There is up to 10cm of new snow in the alpine overlying a variety of surfaces from suncrust on solar aspects to wind slabs and crusts on shaded slopes. Strong S'ly winds are forming new windslabs. Crusts in the top 20cm are weakening with continued warm temps and triggering of deeper layers is possible.

Avalanche Summary

No new avalanches were observed yesterday but visibility was poor. On Tues skiers ski cut a size 2.5 from a steep S asp at 2350m. The avalanche ran several hundred meters entraining the moist surface snow. North of the Park a size 3 skier triggered avalanche resulted in a fatality. This showed that while unlikely, triggering deep slabs is possible.

Confidence

Timing, track, or intensity of incoming weather system is uncertain

Avalanche Problems

Wind Slabs

New moist snow, with strong southerly winds are forming new windslabs in the alpine. They may bond poorly in areas where they overly crusts, or may be hiding deeper old windslabs. Continued warm temps are making the old windslabs more reactive.

Be careful with wind loaded pockets, especially near ridge crests and roll-overs.Avoid freshly wind loaded features.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

Expected Size: 1 - 3

Loose Wet

At treeline and below warm temps and rain is further weakening the snowpack. The weak, moist surface snow may be easily triggered on steep slopes, gaining mass and traveling long distances.

Avoid avalanche terrain during periods of rain.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