Archived

Avalanche Forecast

Mar 18th, 2013–Mar 19th, 2013

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

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

3: Considerable

The avalanche danger rating below treeline will be considerable

Regions: Glacier.

Slab and loose avalanches can be easily triggered by riders today with fresh snow overtop a crust.

Weather Forecast

Unsettled moist weather pattern producing convective storms with light to locally moderate amounts. A brief ridge of high pressure on Tuesday keeping things dry with sunny skies before a Pacific frontal system arrives on Wednesday bringing moderate amounts of precipitation.

Snowpack Summary

30cm of low density snow over the Mar 16th crust of varying thickness depending on elevation below 2000m. Moist snow below the crust. This overlies a well settled mid pack. The Feb 12 SH is down around 100-150cm.

Avalanche Summary

Several skier triggered avalanches in the Hermit area yesterday to size 1.0. These were low density slabs sliding on a crust down 15cm with surprisingly wide propagation running far and fast.7 natural slab avalanches in the highway corridor ranging in size from 2.0 to 2.5

Confidence

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

Avalanche Problems

Storm Slabs

A buried rain crust is providing an ideal bed surface for new snow avalanches below 2000m. There's around 30cm overtop and was really reactive yesterday to rider triggering with wide propagation, running far and fast.

Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Likely

Expected Size: 1 - 2

Wind Slabs

Moderate south winds and new snow available for transport mean that you could expect windslabs on lee terrain above treeline.

Avoid freshly wind loaded features.

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

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 1 - 2

Persistent Slabs

It will likely take a large trigger, like a cornice or another avalanche to trigger the surface hoar/crust layer from February down 1-1.5m. The resulting avalanche would be very large and destructive if triggered.

Be aware of the potential for large, deep avalanches due to the presence of buried surface hoar.Avoid shallow snowpack areas where triggering is more likely.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Unlikely - Possible

Expected Size: 3 - 4