3 Dec 2012

We experienced a break yesterday afternoon between the series of weather systems that have given us over 1 meter of snow in the past 5 days. Avalanche control on Blackcomb Whistler yesterday produced up to size 2 avalanches in isolated terrain features with explosives.

As of 06:30 the temperature at 2260 meters was -7, winds were 50-70 KPH from the SE. At pig alley 1650 meters the temperature was -3.5, 22 cm of new snow was recorded there over night. In the valley it is +1.

There will be a lull in the active weather pattern we have been experiencing today, sunny periods are forecasted for this afternoon. Flurries could bring 3-5 cm during the day giving way to a further 25-30 cm by Tuesday morning. Moderate snow fall amounts could bring a further 15-20 by Wednesday morning. Freezing levels continue to slowly creep with fluctuation's toward the valley floor. Its very difficult to forecast amounts with the size of this low and the multiple waves of precipitation.
Freezing level should be in the valley by Wednesday, models are trending toward cooler temps and 10-20 cm each day until at least Saturday.

For the latest local avalanche advisory: Still at High

This is a big read, but if you take the parts specific to our zone it can be helpful in understanding the weather patterns. From Nav Canada: Seasonal Weather and Local Effects

 Snow Report from France: It has been snowing

Settlement, an important factor in snow stability. For instance, yesterdays snow settled from a snow base of 170 cm measured at 06:30 at pig alley to 168 cm measured at 14:00 after receiving 7 cm of snow during the day.  At the Catskinner weather plot the HS yesterday morning was 134 cm as of 06:30, 7 cm fell there during the day, as of 14:30 the HS was 135 cm.  Not a significant amount of settlement, when it snows every day its hard to get to 25 % . This is when skier compaction becomes crucial in snow stability if the hazard is acceptable and control work can be incorporated into the equation.

Definition:  The progressive densification (consolidation) of a snowpack due to gravity, overburden pressure (of overlying snow) and metamorphism. In general, substantial settlement (25%) of new snow layers is a stabilizing influence on a mountain snowpack.

    A hooded merganser flys towards an unsuspecting swan on a slushy Green Lake.