Avalanche Forecast

Issued: Nov 28th, 2015 8:04AM

The alpine rating is below threshold, the treeline rating is below threshold, and the below treeline rating is below threshold. Known problems include Loose Wet, Wind Slabs and Deep Persistent Slabs.

bcorrigan, Avalanche Canada

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

Summary

Confidence

Fair - Due to the number and quality of field observations

Weather Forecast

An arctic high 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.

Avalanche Summary

No recent avalanche activity has been reported, but previous reports were about sluffing in steep terrain on S. facing slopes in the alpine.

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 has been reported building in sheltered locations. 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 will likely build a sun/temperature crust on solar aspects. The current warm temps and solar input will create a sun/temperature crust as the snowpack cools down.

Problems

Loose Wet

Warm temperatures and solar input may create loose wet avalanche conditions on sun-drenched slopes

Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.>

Aspects: North, North East, East, South East.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 4

Wind Slabs

Wind slabs on south slopes especially just below ridge tops may be triggered by skiers or sledders

Avoid freshly wind loaded features.>Avoid travelling in areas that have been reverse loaded by winds.>Be cautious as you transition into wind affected terrain.>

Aspects: North, North East, East.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Deep Persistent Slabs

Facetted crystal have been reported in shallow snowpack areas on north aspects. A collapse of this layer could trigger a large destructive avalanche.

Avoid shallow snowpack areas where triggering is more likely.>Now is a good time to dig a snow profile (or two) and figure out how the snowpack changes with aspect and elevation.>Be aware of thin areas that may propogate to deeper instabilites.>

Aspects: North, North East, East, South East.

Elevations: Alpine.

Likelihood

Unlikely

Expected Size

1 - 4

Valid until: Nov 29th, 2015 2:00PM