Avalanche Forecast

Archived

Feb 11th, 2015–Feb 12th, 2015

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 and human triggered avalanches likely.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches possible, human triggered probable.

Regions

Little Yoho.

Watch temperatures during the day as we are expected to be close to threshold. Sudden intense sun could also be problematic.

Weather Forecast

Light snow, cloudy conditions, and moderate temperatures are expected to continue until the weekend. This is unlikely to reduce the hazard in the short-term.

Snowpack Summary

60-90 cm of recent storm snow overlies a crust. The recent heavy precipitation, wind and warmer temperatures created storm slabs which continue to stress the January 30th crust interface. Isothermal conditions can be encountered below treeline under a varying crust. Winslabs are common in exposed areas at treeline and in the alpine.

Avalanche Summary

Recent avalanche control produced numerous slab avalanches up to size 3. Many of the avalanches started dry and turned wet at lower elevations. Also there was evidence of a widespread cycle up to size 3.5 throughout the forecast region. Some avalanches were running close to full path.

Confidence

Problems

Storm Slabs

Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-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.

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.