We are in a tricky Low Probability, High Consequence cycle. The reality is that large, likely un-survivable avalanches will continue to occur sporadically and are very hard to predict. Manage your exposure and be conservative in terrain selection!
Summary
Weather Forecast
Unsettled weather continues. Today should be mainly cloudy, with isolated flurries and moderate S'ly winds. Freezing levels will rise to 1700m. Overnight continued flurries will accumulate to ~6cm, with mod to strong SW winds. Thurs should be dry with sunny breaks in the afternoon. Friday should be cloudy with flurries adding up to another 8cm.
Snowpack Summary
Recent storm instabilities are gaining strength. Winds have been shifting directions forming windslabs in alpine lee's and adding to the already huge cornices. Mid February PWL's are now down ~150cm and were reactive during last weeks storm. The basal weakness (Nov 13 crust) has been reactive to large triggers (ie cornices and step-downs).
Avalanche Summary
The snowpack has demonstrated it's potential to produce very destructive avalanches. For example, on Sat Macdonald West Shoulder avalanched naturally ripping out mature timber and running to the valley floor. Sporadic avalanches continue to occur, like
this one in the Smart drainage on Monday, showing wide propagation and multiple step down layers.
Confidence
danyelle magnan,
Parks Canada
