Archived

Avalanche Forecast

Feb 8th, 2017–Feb 11th, 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: Waterton Lakes.

Incoming wind and snowfall will produce fresh wind and storm slabs. With130cm of previous storm snow available for entrainment, even avalanches that start small could accumulate significant destructive potential as they travel downhill.

Weather Forecast

Thursday: Warming (+6 degrees at valley bottom, 1700m Freezing level), Strong to Extreme SW winds, Periods of snow (Up to 40cm)Friday: Scattered clouds, Flurries, Ongoing wind, slight cooling (High 1).Saturday: Clear, Light Wind, High 0.

Snowpack Summary

Up to 130cm of recent storm snow from last weekend is now available for wind transport. Below this is wind-hardened snow exposed areas, near surface facets in sheltered areas, and a melt-freeze crust below 2000m on solar aspects. The lower snowpack facets remain as a persistent concern and have produced isolated Sudden results in snowpack tests.

Avalanche Summary

A concerning lack of natural activity was observed in the wake of last weekends storm. Most starting zones are still holding up to 130cm of fresh storm snow.

Confidence

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

Avalanche Problems

Wind Slabs

Expect rapid Wind Slab development with incoming weather system.

Avoid all avalanche terrain during periods of heavy loading from wind and new snow.Minimize overhead exposure; avalanches triggered by windloading may reach run out zones.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Likely - Very Likely

Expected Size: 2 - 3

Storm Slabs

Avoid all avalanche terrain.The new snow will require several days to settle and stabilize.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Likely - Very Likely

Expected Size: 2 - 3

Deep Persistent Slabs

Weak layers from a cold winter have produced few results in recent testing, but are now being heavily loaded, time will tell when the tipping point is reached for these to come back to life.

If triggered the storm/wind slabs may step down to deeper layers resulting in large avalanches.Avoid exposure to overhead avalanche terrain, large avalanches may reach the end of run out zones.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Possible

Expected Size: 3 - 4