Backcountry Advisory 

As of Wednesday, Jan. 2

Our tranquil Christmas holiday is officially over courtesy of the Pineapple express direct from Hawaii. The big protective high pressure ridge which dominated the province since Dec. 19 has now finally broken down and the wolves are at the gate. The first frontal onslaught is currently hosing us down up to treeline, with a rather stiff new slab developing up in the alpine. As of Wednesday the skiing can best be described as appalling, but not to worry. All this may yet turn out to be a blessing in disguise.

The Christmas calm spell saw a steady strengthening in the snowpack under a regime of moderate air temperatures and solar effects. An exception to this trend was a variety of effects upon the snow surface. Most concerning was the formation of feathery surface hoar crystals under a series of clear night skies. Other red flags were the formation of faceted crystals in the top layer as well as suncrust formation on solar affected aspects.

All the above are potential weak interfaces with any new snow and can persist for long periods of time. The cure for most of these problems is just what we are getting; a good dose of rain. The surface hoar washes away and the faceted crystals should begin to round out and bond together.

As temperatures drop behind the front the wet snow surface will freeze into a slick crust and will likely become the next potential weakness to watch as further new snowfalls accumulate.

The other red flag is our November crust and facet combination in the bottom of the snowpack. It is notable that all the spectacular avalanche activity in the Blackcomb Glacier and West Bowl back on Dec. 19 released on this layer. In shallow snowpack areas this weakness remains significant and requires only a little loading to produce destructive avalanches. Be extremely wary of windward and rocky terrain features where areas of wind deposition and scouring occur in close proximity. This is classic terrain for the formation of faceted weaknesses. The problem is that due to the generally windward exposure these areas don't always load up, thus can be rather unpredictable.

The weather forecast calls for unsettled showery and cooler conditions until Saturday with the next significant frontal system scheduled to arrive Sunday. Until then the Avalanche Danger Rating is LOW at treeline and below. It’s MODERATE up in the Alpine. Sunday’s storm should trend the rating to CONSIDERABLE. For daily backcountry advisories for areas surrounding the Whistler and Blackcomb ski areas call 604-938-7676. For areas further afield consult the Public Avalanche Bulletin at 1-800-667-1105 or WWW. AVALANCHE.CA.


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