Avalanche Forecast

Poor - Timing, track, or intensity of incoming weather is uncertain

Moderate precipitation amounts are forecast for the interior mountains overnight into Friday morning. The freezing levels will lower to valley bottom overnight and then rise to about 800 metres under mostly clear skies and drier conditions after the snow ends Friday morning. The next system is forecast to move into the interior on Saturday afternoon. The approaching system is forecast to bring moderate to heavy precipitation combined with strong southwest winds and freezing levels rising to about 2000 metres. Heavy precipitation is forecast to continue on Sunday morning, ending sometime during the day Sunday.

We don't have a lot of avalanche observations from the region today. Natural and explosive controlled avalanches up to size 3.0 and historically large for known paths were reported from the Dogtooth area on Thursday. What we have heard is that the weak base layers are being over-loaded by the recent storm snow resulting in full depth avalanches. These results are probably more likely in areas that have a thinner weaker snowpack. These conditions may be difficult to identify now that the storm snow has arrived.

Parts of the region have received up to 60cm of new snow in the past few days. Remember these amounts could differ locally inside your region. This new snow, wind and warmer temps have been the perfect recipe for slab development. There is likely variable wind slab formation on all exposed areas. The average, snowpack depths are looking like 70-90cm at treeline and probably 100-160. The basal layers in our current snowpack are proving to be very weak. Reports from the field are indicating that this facet/crust/depth hoar combo has reached its threshold and natural avalanche activity is happening. Avalanches are running to ground with wide propagation. The November 7th surface hoar layer is also down quite deep in the snowpack, ranging around the meter mark. There have been no confirmations of that layer being reactive, it seems like most things are running to ground or within the storm snow. The snowpack in the Purcells is highly variable in distribution. There may not be enough snow below treeline to create an avalanche problem, but problems from above could run into this elevation. Forecasters today will be posting a post storm strategy blog. This will entail different out comes of how fast or slow our snowpack may heal during and/or after these storms hit.