Avalanche Forecast

Archived

Jan 4th, 2014–Jan 5th, 2014

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Regions

Sea To Sky.

Confidence

Fair - Freezing levels are uncertain

Weather Forecast

Sunday: Mix of sun and cloud with an area of warm air moving into alpine elevations. Above freezing temperatures are expected in the Alpine.Monday: Continued warm air at higher elevations with light to moderate Southwest winds and no precipitation.Tuesday: Cloudy with light to moderate Southwest winds and seasonal temperatures in the alpine.

Avalanche Summary

Natural avalanches up to size 2.0 were observed that released in pockets of wind transported storm snow on South and Southeast aspects that were about 25 cm deep. There was one observation of a size 3.0 natural storm slab avalanche on Northeast aspect in the Pemberton area that appeared to have been triggered by loose snow sloughing from steep terrain. There was a skier remote triggered avalanche size 1.0-2.0 and a skier accidental triggered avalanche size 2.0 on a steep rocky shallow facetted slope in the Whistler backcountry.

Snowpack Summary

20-40 cm of recent storm snow has settled into a soft storm slab. In some areas the wind has transported this available snow into a moderately stiff wind slab at higher elevations. Ski penetration has been reported to be about 15 cm and foot penetration is about 25 cm in the alpine, and about 60 cm below treeline in weak facetted snowpacks. Basal depth hoar in shallow snowpack areas also remain a concern, particularly on south aspects. Forecast warm alpine temperatures over the next few days may release weak cornices or loose moist snow from steep solar exposed aspects. Early season riding hazards such as rocks, stumps and logs are lurking below the surface in many areas. In glaciated terrain open and poorly bridged crevasses are everywhere.

Problems

Wind Slabs

Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.

Persistent Slabs

Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.

Loose Wet

Loose Wet avalanches are the release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry Avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.