Archived

Avalanche Forecast

Jan 9th, 2019–Jan 10th, 2019

Alpine

4: High

The avalanche danger rating in the alpine will be high

Treeline

3: Considerable

The avalanche danger rating at treeline will be considerable

Below Treeline

3: Considerable

The avalanche danger rating below treeline will be considerable

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

3: Considerable

The avalanche danger rating at treeline will be considerable

Below Treeline

2: Moderate

The avalanche danger rating below treeline will be moderate

Regions: Sea To Sky.

More snow, wind and rising temperatures are creating a widespread storm slab problem. Dial back your exposure to avalanche terrain as the storm rolls through.

Confidence

Moderate - Intensity of incoming weather systems is uncertain

Weather Forecast

WEDNESDAY NIGHT: Snow, accumulating 20-30 cm. Strong south wind. Freezing level rising above 1300 m.THURSDAY: Snow, accumulating 10-20 cm. Strong south-southwest wind. Freezing level 1600 m.FRIDAY: Flurries, up to 10 cm accumulation. Moderate south wind. Freezing level rising above 1600 m.SATURDAY: Mix of sun and cloud. Light to moderate south wind. Freezing level above 2000 m.More details can be found in the Mountain Weather Forecast.

Avalanche Summary

Several small wind slabs were triggered by skiers near ridge crest on Monday. On Wednesday, size 2 storm slab avalanches where triggered by explosives and skiers. Additionally, a large (size 2) cornice failed under the weight of a person. Incoming weather is expected to create new storm slabs.

Snowpack Summary

20-40 cm new snow adds to the previous 150+ cm of settled storm snow. Another 20 cm is expected by Friday morning as freezing levels rise. New snow, wind and warming are expected to build new storm slabs. Cornices are also likely to grow larger.The new snow will bury old wind slabs on a variety of slopes at alpine and treeline elevations. At treeline and below, two weak layers exist in the upper 2 m of the snowpack. These layers consist of surface hoar (feathery crystals) in more sheltered areas and a crust on solar aspects and on all aspects below 1600m.In the lower snowpack, a crust/facet (sugar snow) layer is now over 2 m deep. There have been no recent reports of avalanches on this layer, but it may still be reactive to heavy loads (such as a cornice fall) in isolated areas.

Avalanche Problems

Storm Slabs

New snow, wind, and warming are expected to build storm slabs that can be triggered by the weight of a person. The deepest and most sensitive deposits of snow will be found in wind-loaded terrain.

Be careful with wind loaded pockets, especially near ridge crests and roll-overs.Minimize overhead exposure during periods of heavy loading and rapid warming.If triggered the storm slabs may step down to deeper layers resulting in large avalanches.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Likely

Expected Size: 1.5 - 2.5

Loose Wet

Freezing levels are rising. The chance for loose, wet avalanches will increase as the snowpack warms.

Watch for clues, like sluffing off of cliffs, that the snowpack is warming up. Minimize exposure to steep slopes during rapid loading.

Aspects: All aspects.

Elevations: Treeline, Below Treeline.

Likelihood: Possible

Expected Size: 1 - 1.5