Archived

Avalanche Forecast

Apr 4th, 2015–Apr 5th, 2015

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

1: Low

The avalanche danger rating below treeline will be low

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

1: Low

The avalanche danger rating below treeline will be low

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

1: Low

The avalanche danger rating below treeline will be low

Regions: Glacier.

Although temperatures have dropped, a couple more cold nights are needed to neutralize instabilities in the upper snowpack.

Weather Forecast

An unstable weather pattern will bring flurries and up to 9cm of snow this morning. Freezing levels rise to 1500m this afternoon with an alpine high of -3. Ridge winds west 10-30km/h. A clearing trend begins early this evening with cold temperatures and clear periods overnight. A mix of sun and cloud forecast for Sunday.

Snowpack Summary

Cold temps overnight have cooled surface snow and formed a 10cm crust at lower elevations. The middle snowpack is still warm, with moist snow down to 70cm at treeline. Rapidly settling storm snowÂ (30-40cm) is sitting atop 6cm wet layer that is showing weakness in stability tests. Lower snowpack is well settled. Suspect wind slabs near ridges.

Avalanche Summary

No new natural avalanches were observed in Glacier National Park yesterday.

Confidence

Timing or intensity of solar radiation is uncertain

Avalanche Problems

Storm Slabs

30-40cm of rapidly settling storm snow sits over a weak wet layer below 2300m. Stability tests indicate that this layer is triggerable by light loads. At higher elevations moderate winds have created pockets of wind slab and fragile cornices.

The new snow will require several days to settle and stabilize.Be cautious as you transition into wind affected terrain.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 1 - 3

Persistent Slabs

A series of weak layers in the top 1.5m of the snowpack are more easily triggered due to the load added by the new snow and rain over the past week. They may be triggered by the added load of a person, another avalanche or a cornice falling.

Use conservative route selection, choose moderate angled and supported terrain with low consequence.Pay attention to overhead hazards like cornices.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Unlikely - Possible

Expected Size: 2 - 3