Archived

Avalanche Forecast

Mar 21st, 2014–Mar 22nd, 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

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

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

2: Moderate

The avalanche danger rating below treeline will be moderate

Regions: Glacier.

Solar radiation is unpredictable at this time of year. When the sun comes out, it comes out strong and could affect those buried weak layers to cause avalanches or cornices to break. Pay attention to this and make the appropriate decisions.

Weather Forecast

Unstable weather pattern over the interior will result in light snow amounts with mainly cloudy skies with possible breaks throughout the day. A weak ridge of high pressure will build for tomorrow clearing the skies a little more for Saturday

Snowpack Summary

15cm of new low density snow sits over 60cm of settling snow. Both the Mar 13 (down ~50cm) and the Mar 2 (down ~1m) crust/surface hoar layers are becoming patchy but reactive in snowpack tests where they exist. The Feb 10-Jan22 layers are down 1.5-2m and continue to show step down potential.

Avalanche Summary

8 natural avalanches size 2.5 to 3.0 were observed in the east of the Rogers Pass summit highway corridor.

Confidence

Timing or intensity of solar radiation is uncertain on Saturday

Avalanche Problems

Storm Slabs

Snow amounts have slowly been accumulating over the last few days and storm snow instabilities may catch you by surprise. Caution on unsupported slopes or wind affected areas. This new snow is likely to produce some fast sluffing on steep slopes.

Be cautious as you transition into wind affected terrain.Be aware of party members below you that may be exposed to your sluffs.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 1 - 3

Persistent Slabs

This layer is deep enough to cause a large avalanche and shallow enough to be triggered by people, a dangerous combination. It's been most reactive on solar aspects where the crust is thickest and most likely to be triggered from shallow snow areas.

Choose well supported terrain without convexities.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 2 - 3

Deep Persistent Slabs

The deepest instability within our snowpack is down around 2m. Large triggers have produced very big avalanches on this layer into last week. It remains on our watch list, and it's another reason to avoid shallow snowpack areas.

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

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Unlikely

Expected Size: 2 - 4