Backcountry Advisory 

Avalanches running within storm snow as well as on old surfaces

As of Wednesday, March 8

Alpine: CONSIDERABLE trending to HIGH

Treeline: CONSIDERABLE trending to HIGH

Below Treeline: MODERATE trending to CONSIDERABLE

Travel Advisory: 60 cm of snow has fallen since Saturday night. Mountain top winds during this period have been strong for extended periods, from predominantly the Southeasterly direction. An additional 25-40 cm of snow is expected to fall during the next 24 hours accompanied by strong mountain top winds. It is advisable to give the storm snow layers a few days to tighten in after the passage of the storm before attempting any of the more aggressive lines out there.

Avalanche Activity: We have seen widespread avalanche activity periodically during the past week, with avalanches running within the storm snow as well as on the old surfaces that date back to Feb. 21. Soft slabs from 30 to 60 cm in depth were observed to remain reactive to explosive and ski testing yesterday morning. Widespread natural avalanche activity was observed during the height of the storm, but abated as temperatures fell with the arrival of the cold front, which aided the storm snow layers in tightening in.

Snowpack: The storm snow layers that have fallen during the past week are resting on a variety of old surfaces from stiff and wind affected, to softer low density layers, facets, crusts, as well as surface hoar below the treeline. In some rocky terrain the snowpack turned to facets during the recent spell of cold temperatures, and we have started to see some sporadic avalanche activity in some of these areas. More such activity can be expected with further loading over the next few days. Below treeline a layer of surface hoar that formed on Saturday night is now buried by 45 cm of new snow. We may also see avalanche activity begin within this layer in some isolated areas below the treeline. Avoid any terrain trap such as creek beds and gullies. At lower elevations and on Southerly aspects there is a melt-freeze crust buried under the loose surface layers of snow.

Weather: A strong frontal system is arriving in our region this morning bringing from 25 to 40 cm of snow through tomorrow, with continued strong South-westerly winds. The freezing level is expected to fluctuate between the valley and 1,000 metres during this period. Friday and Saturday should usher in a cool, unstable air mass, with a chance of colder arctic air arriving in our region early next week.

Conditions may vary and can change rapidly. Check for the most current conditions before heading out into the backcountry. Daily updates for the areas adjacent to Whistler/Blackcomb are available at 604-938-7676, or at www.whistler-blackcomb.com/weather where there is also a link to the CAA public avalanche bulletin, or call 1-800-667-1105.

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