Archived

Avalanche Forecast

Feb 22nd, 2013–Feb 23rd, 2013

Alpine

4: High

The avalanche danger rating in the alpine will be high

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

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: Purcells.

Significant snowpack and weather variations exist throughout the region. Be aware of conditions that are specific to your area and make observations continuously as you travel.

Confidence

Poor - Due to limited field observations on Friday

Weather Forecast

Saturday: Light snowfall / Moderate northwest winds (with strong gusts) / Freezing level at surfaceSunday: Light snowfall / Moderate west winds / Freezing level at 1100mMonday: Light snowfall / Light southwest winds / Freezing level at 1000m

Avalanche Summary

Loose snow avalanches to size 1.5 were reported in a few areas; however, observations have been extremely limited due to poor visibility.

Snowpack Summary

Very light to locally moderate amounts of new snow have fallen and may exist as a wind slab in exposed areas. These new accumulations add to a slab which overlies reactive layers of surface hoar that were buried on February 12th and February 15th. These layers currently sit between 15 and 60cm below the surface. The slab may also be reactive on southerly aspects where buried sun crusts exist. Loading from new snow and wind throughout the weekend may cause another cycle of natural activity, or an increased sensitivity to human triggers in deeper snowpack areas. There are older weak layers that are now buried down around 70-80 cms and also at about 110 cms. These layers have been less likely to trigger by skiers, but they may still be sensitive to large loads like avalanches in motion or cornice fall.

Avalanche Problems

Storm Slabs

Recent snowfall amounts are highly variable and somewhat uncertain throughout the region due to limited observations. Where higher accumulations exist, large storm slab avalanches are likely, especially in wind-affected areas.

Be cautious as you transition into wind affected terrain.>Make observations as you travel and watch for clues of instability.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Likely

Expected Size: 1 - 4

Persistent Slabs

Loading from new snow and wind will likely add reactivity to persistent buried surface hoar layers. In deeper snowfall areas, resulting avalanches may be surprisingly large.

Be aware of the potential for large avalanches due to the presence of buried surface hoar.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Likely

Expected Size: 2 - 5