Avalanche Forecast

Archived

Nov 29th, 2015–Nov 30th, 2015

Alpine

Below Threshold.

Treeline

Below Threshold.

Below Treeline

Below Threshold.

Alpine

Below Threshold.

Treeline

Below Threshold.

Below Treeline

Below Threshold.

Alpine

Below Threshold.

Treeline

Below Threshold.

Below Treeline

Below Threshold.

Regions

Cariboos.

Rising temperatures in the alpine may change the snowpack dramatically, especially on solar aspects.A big THANK YOU! to riders sharing their observations with the Mountain Information Network. MIN

Confidence

Fair - Due to the number and quality of field observations

Weather Forecast

A ridge of high pressure continues to dominate the weather pattern over western Canada and is not forecast to move out of the area until Tuesday or Wednesday next week. In the meantime, an above-freezing layer (AFL) of air will pass through the region between 1500 and 3000m bringing temperatures in that elevation band to as high as +5c, especially on solar aspects. Arctic air pooling in the valley bottoms will keep the temperatures well below freezing until the next storm system flushes out the cold air.We can expect valley fog in the mornings, hopefully clearing out by the afternoon.

Avalanche Summary

No reports of avalanches in the Cariboo region from the last few days. If you have observed any, please share your information through the Mountain Information Network

Snowpack Summary

The snowpack is extremely variable at this time, with wind scoured North facing slopes at treeline and above. South facing slopes have wind slabs at tree line and above and may be hiding surface hoar from the previous spell of cold clear weather. Surface facetting has observed in the region as a result of the recent cold weather and clear skies, and surface hoar as large as 40mm has been reported building in sheltered locations below tree line! There are a number of surface hoar layers now buried in the snowpack that seem to be unreactive, with the most recent having been buried on Nov 24th. In shallow snowpack areas, especially on northern aspect, there is a weak facetted layer at the base of the snowpack. Warming temperatures and strong solar radiation has built a sun crust on solar aspects.

Problems

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.

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.

Deep Persistent Slabs

Deep Persistent Slab avalanches are the release of a thick cohesive layer of hard snow (a slab), when the bond breaks between the slab and an underlying persistent weak layer deep in the snowpack. The most common persistent weak layers involved in deep, persistent slabs are depth hoar or facets surrounding a deeply buried crust. Deep Persistent Slabs are typically hard to trigger, are very destructive and dangerous due to the large mass of snow involved, and can persist for months once developed. They are often triggered from areas where the snow is shallow and weak, and are particularly difficult to forecast for and manage.