Archived

Avalanche Forecast

Apr 8th, 2015–Apr 9th, 2015

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

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

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

Regions: Northwest Inland.

Observations and data are limited. Be sure to read the Northwest Coast bulletin for information on a touchy persistent slab problem, which may also be present and active in some inland areas.

Confidence

Poor - Due to the number of field observations

Weather Forecast

Thursday: Increasing cloud with light snow developing late. The freezing level is around 1500 m. Winds increase to strong or extreme from the S-SW. Friday: Light snow. The freezing level is near 1200 m and winds are strong from the south. Saturday: Cloudy with flurries. The freezing level is around 1000 m and winds are moderate from the SW.

Avalanche Summary

On Tuesday, several loose wet avalanches to size 2 were reported from steep sun-exposed slopes. Some of these did trigger slabs up to size 2.5, potentially releasing on the March 25th surface hoar layer. Observers near the Ningunsaw Pass (northern part of the region) have been reported significant activity on the March 25th interface. For the past few days there have been reports of natural, skier-triggered, and remotely triggered avalanches up to size 3.

Snowpack Summary

You may still find dry powder on higher north aspects, but any sun exposed slope will likely be in a melt-freeze cycle. Recent winds have scoured windward slopes and loaded lee features. A crust with surface hoar buried on March 25th, down around 50 cm, has been identified as a potential problem in parts of the forecast region, but its sensitively and distribution are largely unknown. At the base of the snowpack, especially in areas of shallow snow, weak facets may be found. Cornices are now large and potentially fragile, and solar aspects are becoming active in the late afternoons.

Avalanche Problems

Persistent Slabs

A buried surface hoar layer, down around 50 cm, has been very reactive in the Ningunsaw Pass area and could be an issue in other parts of the region where we receive little info.

Dig down to find and test weak layers before committing to a line.>Choose conservative lines and watch for clues of instability.>Be aware of the potential for large, deep avalanches due to the presence of buried surface hoar.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 1 - 4

Wind Slabs

Winds are forecast to increase with the approaching frontal system. Any loose snow will be blown into thin wind slabs in exposed lee terrain, possibly well below ridge crests.

Use ridges or ribs to avoid pockets of wind loaded snow.>Be cautious as you transition into wind affected terrain.>

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

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 1 - 3