Archived

Avalanche Forecast

Feb 25th, 2018–Feb 26th, 2018

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

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

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: Northwest Inland.

Touchy wind slabs can be found in many alpine and treeline locations.

Confidence

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

Weather Forecast

MONDAY: Mainly cloudy with 5-10 cm snow. Freezing level near 600 m. Strong westerly winds.TUESDAY: Mix of sun and cloud. Freezing level near 400 m. Moderate to strong westerly winds.WEDNESDAY: Mix of sun and cloud with flurries. Freezing level near 400 m. Moderate southerly winds.More details can be found in the Mountain Weather Forecast.

Avalanche Summary

Poor weather has kept avalanche observations to a minimum. It is expected that a natural avalanche cycle is underway at high elevations due to rapid snow and wind loading.

Snowpack Summary

Light snow and strong winds are continuously building wind slabs in open terrain at alpine and treeline elevations. These overlie buried old hard wind slabs, scoured surfaces and sastrugi in many exposed areas. In wind-sheltered terrain, sun crusts or dry facets sit below the recent storm snow.Around 50-150 cm down, you will find a crust/surface hoar layer from mid-January, which still has the chance to surprise you and could be triggered from a thin snowpack spot, or with a large trigger like cornice fall. Facets at the base of the snowpack can possibly be triggered from shallow snowpack areas.

Avalanche Problems

Wind Slabs

Wind slabs are widespread and could be triggered by the weight of a person.

Be cautious as you transition into wind affected terrain.Give cornices a wide berth when travelling on or below ridges.Travel on ridgetops to avoid wind slabs on slopes below.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Likely

Expected Size: 1 - 2.5

Persistent Slabs

Buried weak layers are most likely to be triggered from thin or variable depth snowpack areas; or with a large load like a cornice fall.

If triggered the storm/wind slabs may step down to deeper layers resulting in large avalanches.Avoid thin, rocky or sparsely-treed slopes.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Unlikely - Possible

Expected Size: 1.5 - 3.5