Sea To Sky

New snow and sunshine will make the mountains very inviting over the next few days; however, the complex snowpack and potential for triggering large avalanches requires some patience and conservative terrain choices.

Fair - Due to limited field observations

Thursday should be mainly sunny during the day with a chance of light precipitation and gusty NW winds late in the day and overnight as a cold front pushes through. An above freezing layer is possible between 1400-2500m on Thursday. We should see a return to sun with moderate NW winds on Friday morning as the ridge of high pressure re-establishes. Sunny and cool conditions are forecast for Saturday and Sunday. The freezing level should hover around 1500-2000m on Friday and Saturday.

There is a report of a Size 2 skier triggered avalanche near Whistler on Tuesday that resulted in minor injuries. Explosives control work on Monday produced several large avalanches including one very impressive Size 4 avalanche in the Blackcomb backcountry. Many of these avalanches were from paths that recently released and were reloaded during the storms on the weekend. Several released in low angle terrain and ran very far.

We are dealing with a complex and somewhat unusual snowpack for the South Coast. Around Whistler there are several different persistent weak layer deep in the snowpack including a layer of depth hoar right near the base of the snowpack and at least two distinct crust/facet combinations between 50-100cm above the ground. Recent storms have dumped up to 200cm of snow on top of the weak underlying snowpack. This new load resulted in many large avalanches during the storm and several large to very large human or explosive triggered avalanches shortly after the storm. Keep in mind that rain followed by cooler temperatures have helped to stabilize the snowpack at and below treeline. The greatest concern is with slopes above 1900m that have not recently avalanched. This is not the classic coastal instability where you can charge hard a few days after the storm. Be patient and realize that a large avalanche may become more difficult to trigger over time, but the consequences of a deep release could be devastating.