Archived

Avalanche Forecast

Mar 12th, 2017–Mar 13th, 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

3: Considerable

The avalanche danger rating at treeline will be considerable

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

3: Considerable

The avalanche danger rating below treeline will be considerable

Regions: Glacier.

A natural avalanche cycle is hitting the Rogers Pass area today. Large avalanches are running down to the valley floor. Today would be a great day to hit the ski hill!!

Weather Forecast

Flurries should bring another 5cm today with moderate southerly winds and freezing levels around 1500m. More snow is expected over the next few days, with 10-15cm on Monday, 10cm on Tuesday, and another 10cm Wednesday. Freezing levels will increase each day, reaching 2000m by Wednesday. This will keep the danger ratings elevated.

Snowpack Summary

Another 20cm last night brings the 3 day total to 70cm. Warming temp's and strong southerly winds are creating a reactive storm slab at the surface. This slab is failing on a mixed form layer on N and E aspects. The late Feb crusts are buried 70-120cm deep on solar aspects depending on elevation. Cornices are growing with the winds and new snow.

Avalanche Summary

Natural and artillery triggered avalanches to size 4 are running full path to the valley floor this morning. Natural avalanche activity will continue throughout today. Human-triggered avalanches are very likely at all elevations.

Confidence

Avalanche Problems

Storm Slabs

Steady snowfall this week (70cm in 3 days) and warming temps today have produced a touchy storm. Yesterday this storm slab was able to step down to deeper layers and ran full path.

Avoid exposure to overhead avalanche terrain, large avalanches may reach the end of run out zones.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: 2 - 4

Persistent Slabs

Buried crusts on South and West aspects are hidden under the March snow. Skiers were able to trigger slab avalanches on this layer earlier in the week. Recent storm snow has a high potential to dig down and trigger these deeper slabs.

Avoid shallow snowpack areas where triggering is more likely.Avoid unsupported slopes.

Aspects: North, North East, East, South East.

Elevations: All elevations.

Likelihood: Possible - Likely

Expected Size: 2 - 4

Cornices

Warm temperatures, moderate to strong southerly winds, and plenty of snow for transport are building large cornices at ridge-top. The fresh cornices will be very fragile and could trigger deep slabs.

Pay attention to overhead hazards like cornices which could easily trigger the deep persistent slab.

Aspects: North, North East, East, South East.

Elevations: Alpine.

Likelihood: Likely

Expected Size: 2 - 4