Avalanche Forecast

Archived

Nov 24th, 2013–Nov 25th, 2013

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.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely.

Below Treeline

Natural avalanches unlikely.

Regions

South Columbia.

This forecast was produced with limited data. If you have field information please send it to:[email protected]

Confidence

Poor - Due to the number and quality of field observations

Weather Forecast

A ridge of high pressure continues to dominate over southern BC for the next few days with no precipitation in sight for the forecast period. Warmer temperatures at upper elevations and associated valley fog is developing over the southern interior with freezing levels expected to go up to 3100 M. Valleys will remain cool with pooling of cold air, forecast winds at upper elevations are forecast to be light to moderate for the region.

Avalanche Summary

Wet sluffs and pin-wheeling have been reported on S facing alpine slopes above 1700 M with the recent temperature inversion. No other reports of recent avalanche activity have been received. This may speak more to the lack of reported observations rather than actual conditions. If you have information please feel free to contact us at: [email protected]

Snowpack Summary

Recent storm snow continues to settle and is gaining strength with time and warm temps. Wind slabs linger in lee terrain. Surface hoar buried in early November exists in the mid snowpack but due to a lack of data little is known about its reactivity and distribution. The October crust/facet interface buried near the base of the snowpack is still a concern. Surface hoar continues to develop at valley fog levels and in sheltered north aspects.

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.