6 Dec 2011

Persistent Weak layers: This picture shows the formation of the December 4, 2007 crust which was very active,  went to sleep, woke up went dormant and then woke up again on May 17 th and produced some very large Spring Time  Avalanches. The temperatures went to + 17 degrees on that day and there were several large events in the Whistler  Area. When this crust formed it rained to 2200 meters, the rain percolated down about 40 centimetres into the new snow and accumulated on a buried surface hoar layer. That winter was a prime example of a snow pack with a  Persistent weak Layer. Click here to see the definition of PWL. Persistent weak Layers
This result occurred 163 days after the formation of the crust.