Archived

Avalanche Forecast

Mar 15th, 2017–Mar 16th, 2017

Alpine

4: High

The avalanche danger rating in the alpine will be high

Treeline

4: High

The avalanche danger rating at treeline will be high

Below Treeline

4: High

The avalanche danger rating below treeline will be high

Alpine

4: High

The avalanche danger rating in the alpine will be high

Treeline

4: High

The avalanche danger rating at treeline will be high

Below Treeline

3: Considerable

The avalanche danger rating below treeline will be considerable

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.

WE ARE IN AN AVALANCHE CYCLE. Avoid overhead hazard and choose only simple terrain.

Weather Forecast

Periods of snow with up to 13cm accumulation. This precipitation will fall as rain below 1800m. Light ridgetop winds should accompany the snow fall. Another 15cm of snow along with gusty SW winds is forecast for tonight with freezing level coming down to 1400m. The avalanche danger will remain elevated.

Snowpack Summary

High freezing levels (2100m) along with warm moist air continues to effect the snowpack. 60cm+/- of fresh snow has fallen over the last few days accompanied by moderate southerly winds. This has lead to the formation of touchy warm storm slab at all elevation bands. The persistent weak layer buried late February can be found down 80-140cm.

Avalanche Summary

We are in an avalanche cycle. A dozen natural avalanches to size 3 were observed this morning in the highway corridor with some running to the end of path. Four lower elevation fresh point release slides were observed near Ross Peak slide path. These slides appeared to be digging deeper into the snowpack as the slide debris was dirty.

Confidence

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

Avalanche Problems

Storm Slabs

The recent storm snow is rapidly settling into a touchy storm slab, sensitive to both natural and human triggering. The slabs may be more touchy on recently loaded lee features.

The new snow will require several days to settle and stabilize.If triggered the storm/wind slabs may step down to deeper layers resulting in large avalanches.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Very Likely

Expected Size: 1 - 4

Persistent Slabs

Several persistent weak layers are in the upper snowpack. There is step down potential for storm slab releases to dig down to these layers resulting in large dangerous avalanches.

Watch for whumpfing, hollow sounds, and shooting cracks.Use conservative route selection, choose moderate angled and supported terrain with low consequence.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Likely

Expected Size: 1 - 3