Archived

Avalanche Forecast

Jan 26th, 2016–Jan 27th, 2016

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

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

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

Regions: Glacier.

The persistent slab is at a critical depth right now, maybe you might trigger it, maybe you won't. Dig down and evaluate the snow before committing to your line.

Weather Forecast

A small storm rolls through Rogers Pass today, bringing 5-10cm of snow, moderate SW winds, and rising freezing levels (up to 1400m). A lull in storm systems is expected for most of Wednesday, but then a warm, wet storm smacks into the region Wed night. Freezing levels should rise to 1800m with 30-40cm of snow and strong SW winds.

Snowpack Summary

Variable wind-effect in the alpine was observed, with old avalanche crown-lines filled in from the mod-strong SW winds. Below tree-line, with the mild temp's, the new snow is settling into a reactive slab. Whumphing and cracking was also reported in sheltered locations with the suspect layer being the Jan 4th persistent weak layer.

Avalanche Summary

Observations of old avalanches showed significant propagation from alpine and tree-line features, suggesting the storm slabs propagated down to the Jan 4 surface hoar/sun crust layer. Several natural avalanches from yesterday were observed, with a notable size 3 from Tupper (Single Bench path) and 2 sz 2.5's from steep, N-facing tree-line paths.

Confidence

Freezing levels are uncertain

Avalanche Problems

Persistent Slabs

The January 4th interface is getting deep enough in the snowpack to be less reactive to skier loads. Triggered wind slabs, or larger loads like a group of skiers, may be sufficient to wake the Jan 4th up.

Watch for signs of instability such as whumpfing, or cracking. Ride slopes one at a time and spot for your partners from safe locations.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 1 - 3

Wind Slabs

Wind effect from the moderate-strong SW winds during the weekend has loaded up lee features in the alpine and tree-line. The sensitivity of these slabs is uncertain without many observations yesterday.

If triggered the wind slabs may step down to deeper layers resulting in large avalanches.

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

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 1 - 3