Avalanche Forecast
Issued: Jan 7th, 2012 9:42AM
The alpine rating is Storm Slabs, Wet Slabs and Wind Slabs.
, the treeline rating is , and the below treeline rating is Known problems includeSummary
Confidence
Fair - Forecast snowfall amounts are uncertain on Sunday
Weather Forecast
A very strong moist southwest flow is expected to bring about 40 cm of new snow to higher elevations in near coastal areas by Saturday night. Expect winds up to 120 km/hr and freezing levels around 1000 metres rising rapidly to near 1500 metres by Saturday evening. The wind is forecast to moderate to about 60 km/hr by Sunday morning and the freezing level should drop back down to about 1000 metres. There is another heavy pulse of precipitation on Sunday that looks like it will be focused on the area South of Kitimat. This system is forecast to bring another 20 cm of snow to higher elevations around Terrace. If this system moves a little further north, Terrace and Bear Pass could see double this amount. The mountainous areas around Smithers are expected to get 15-20 cm by Sunday morning, and another 10-15 cm by Monday morning. Cooler dry air is expected to follow by Monday noon, and continue to influence the Northwest on Tuesday. Freezing levels should be at valley bottoms by Monday night, and we may see cold outflow winds from the northeast by Tuesday.
Avalanche Summary
A few naturals and explosive controlled avalanches have been reported up to about size 2.5 from the Ningunsaw and further north areas along the highway. A couple of size 2.0 avalanches that slid during the last storm were also reported. There was a wide spread natural cycle reported to have occurred during the last storm.
Snowpack Summary
This description from yesterday has not changed. Rapid loading is expected to be occurring by the time this bulletin is posted. A significant storm dropped 40 to 80 mm of precipitation on this region since Tuesday bringing treeline snowpack depths into the 3-4 m range. The storm was accompanied by high winds and touchy fresh wind slabs and storm slabs now exist as a result. A rain crust formed below about 1000 m, which is not lightly buried with new snow. With all the new snow, earlier weak layers are getting rapidly buried to the point where they are hard to trigger. A relatively thin layer of surface hoar or facets was reportedly buried New Year's day - this may have been the focus of some of the storm snow releases during the current storm; however, I suspect this layer will settle out quite rapidly. Lower down, it is still possible to find a surface hoar/crust/facet combo from mid-December. I suspect it would take a very heavy trigger such as a cornice fall to trigger this layer now, although if you are traveling in an unusually shallow snowpack area I'd still be cautious of it. The lower snowpack is generally well settled and strong.
Problems
Storm Slabs
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Wet Slabs
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Wind Slabs
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Jan 8th, 2012 8:00AM