Avalanche Forecast

Issued: Nov 28th, 2015 7:59AM

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

bcorrigan, Avalanche Canada

South Columbia.

Warming temperatures may push the danger ratings higher, especially on solar aspects. A big THANK YOU ! to all those posting on the 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. Blue skies and dry conditions are 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., and possibly higher 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

Some snowballing from warm temperatures on steep solar aspects, and small loose, dry snow sluffing on steep north facing slopes

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 been observed in the region as a result of the recent cold weather and clear skies, and there will be surface hoar building in sheltered locations. There are a number of surface hoar layers now buried in the snowpack that at present seem to be unreactive, with the most recent having been buried on Nov 24th.In shallow snowpack areas, especially on northern aspects, there may be a weak facetted layer at the base of the snowpack.

Problems

Loose Wet

The warm temperatures at upper elevations may significantly warm the snowpack on solar aspects and create a loose wet hazard, Use caution on sun-drenched slopes at this time.

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

Northerly winds have formed wind slabs on south aspects where we don't usually see them.

The new snow will require several days to settle and stabilize.>Be cautious as you transition out of wind sheltered terrain.>Avoid freshly wind loaded features.>Use ridges or ribs to avoid pockets of wind loaded snow.>Avoid slopes with glide cracks.>

Aspects: North, North East, East.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Deep Persistent Slabs

Weak-facetted snow at the base of the snowpack may exist on north aspects in shallow areas. An avalanche on this layer could be large and destructive.

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.

Elevations: Alpine.

Likelihood

Unlikely

Expected Size

2 - 5

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