Dashboard Regions Weather Stations Radar Alerts Glossary
Contact About
Log In

Register for an account and never miss a forecast again!

Register

Avalanche Forecast

Archived

Feb 14th, 2017–Feb 15th, 2017

Alpine
Natural avalanches possible, human triggered probable.
Treeline
Natural avalanches possible, human triggered probable.
Below Treeline
Natural avalanches unlikely, human triggered possible.
Alpine
Natural avalanches possible, human triggered probable.
Treeline
Natural avalanches possible, human triggered probable.
Below Treeline
Natural avalanches unlikely, human triggered possible.
Alpine
Natural avalanches possible, human triggered probable.
Treeline
Natural avalanches unlikely, human triggered possible.
Below Treeline
Natural avalanches unlikely, human triggered possible.

Regions

South Columbia.

Tricky conditions are expected on Wednesday with warm temperatures continuing, strong winds in the alpine, and new snow/rain. Use a conservative approach and avoid avalanche terrain during periods of rainfall.

Confidence

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

Weather Forecast

A warm storm system reaches the interior on Wednesday morning. 5-10 mm of precipitation is expected during the day on Wednesday with freezing levels around 2500 m in the morning falling to 2000 m in the afternoon. Alpine wind is forecast to be moderate to strong from the southwest. Another 10-20 mm of precipitation is forecast for Wednesday overnight through Thursday afternoon. Freezing levels are forecast to remain around 2000 m on Thursday and alpine wind is forecast to remain moderate to strong from the southwest. Light precipitation is currently forecast to continue Thursday overnight and taper off Friday morning. Friday is forecast to be mostly dry and sunny with freezing levels falling to around 1500 m.

Avalanche Summary

On Monday, natural loose wet avalanches up to size 2 were reported throughout the region from steep sun exposed slopes. A natural size 3 was reported on a northeast aspect at 2500 m and a natural cornice release triggered a size 2 slab on a southeast aspect at 2500 m. A skier also remotely triggered a size 1.5 wind slab on an east aspect at 2400 m which was triggered from 20 m away. On Sunday, a few natural wind slabs were observed in the alpine. A MIN report describes a remotely triggered size 3 avalanche on London Ridge. Click here for more details. On Wednesday, rain at lower elevations is expected to destabilize the upper snowpack resulting loose wet sluffing and potentially increasing the sensitivity of triggering persistent slab avalanches. In the alpine, new snow and strong southwest winds will likely form touchy new wind slabs. Wind slab avalanches have the potential to step down and trigger persistent slab avalanches.

Snowpack Summary

The storm snow from last week has settled rapidly due to the recent mild temperatures. The snow surface is expected to have undergoing melting on Tuesday afternoon on sun exposed slopes. Recent strong winds from the south and west had redistributed the recent storm snow in exposed terrain forming wind slabs. The early February weak layer is typically down 50-80 cm and includes a sun crust on steep sun-exposed slopes, faceted snow, as well as surface hoar on sheltered open slopes. This layer has remained reactive recently and has been the main sliding layer for most of the recent slab avalanche activity. The mid and lower snowpack are generally well settled and stable in deeper snowpack areas but may be faceted and weaker in shallower areas.

Problems

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.

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.

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.