Archived

Avalanche Forecast

Apr 13th, 2017–Apr 14th, 2017

Alpine

2: Moderate

The avalanche danger rating in the alpine will be moderate

Treeline

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

1: Low

The avalanche danger rating below treeline will be low

Alpine

2: Moderate

The avalanche danger rating in the alpine will be moderate

Treeline

1: Low

The avalanche danger rating at treeline will be low

Below Treeline

1: Low

The avalanche danger rating below treeline will be low

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

1: Low

The avalanche danger rating below treeline will be low

Regions: South Coast.

The most likely place to trigger an avalanche is in a very steep gully or in wind affected terrain.

Confidence

Moderate - Timing or intensity of solar radiation is uncertain on Sunday

Weather Forecast

Friday: 5-10 cm new snow expected above elevations of around 1000 m, with rain below that. Some clearing in the afternoon possible. Winds 10-20 km/h from the southwest. Saturday: Flurries. Freezing level around 1000 m. Winds light southwesterly. Sunday: Clearing with some good sunshine. Freezing level rising to 2000 m in the afternoon.

Avalanche Summary

On Friday in the wake of the storm, slab avalanche conditions are most likely to exist in the following locations: a) very steep gullies; and b) on the downwind side of ridges and summits. The recent tragic fatal accident on Mt Harvey indicates the importance of moving very cautiously along corniced ridges, which could be prone to collapse at this time.

Snowpack Summary

There's approximately 20-30 cm of new snow at elevations above 1200 m, with plenty of rain-soaked snow below. The new snow and accompanying southeast winds have set up slab avalanche conditions, particularly on the downwind (northerly and northeasterly) side of ridges and summits. Cornices remain large in some areas and could trigger large avalanches when they fail. Additionally, cornices present a falling hazard and should be given a wide berth while traveling on ridgetops.

Avalanche Problems

Wind Slabs

Expect to find fresh wind slabs reactive to human triggers behind ridgelines and summits.

Be cautious as you transition into wind affected terrain.Use caution in lee areas. Recent wind loading has created wind slabs.Pay attention to changing conditions with elevation.

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

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

Expected Size: 1 - 2

Cornices

Where cornices exist, they are unstable and should be avoided.

Falling cornices can trigger large avalanches.Give cornices a wide berth when travelling on or below ridges.

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

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 1 - 3