North Columbia

More snow, strong winds and warmer temperatures are driving the danger ratings. It's a good time to stick to simple non-avalanche terrain.

Moderate - Forecast snowfall amounts are uncertain on Tuesday

The Interior mountains are under a strong zonal flow which is responsible for pushing out the cold air and bringing in the snow! We can expect to see an additional two - three systems that will move across the region through the forecast period.Tuesday: Snow 10-20 cm with freezing levels rising to 1000 m. Alpine temperatures -9 and ridgetop winds 35-75 km/hr.Wednesday: Light flurries with freezing levels dropping to valley bottom. Alpine temperatures -11 and ridgetop winds 30-45 km/hr.Thursday: Snow 5-10 cm with alpine temperatures -11. Ridgetop winds 15-35 km/h.

On Sunday there was evidence of a natural cycle up to size 3 from larger start zones in the alpine. Given the weather forecast we can expect to see widespread natural avalanche activity on Tuesday.

Up to 35 cm of storm snow (more to come!) sits over a plethora of old snow surfaces including stiff wind affected snow, faceted (sugary) crystals and surface hoar crystals that formed in locations sheltered from the wind. The new snow will likely have a poor bond to these surfaces. Deeper in the snowpack exist two layers that may become reactive through these next series of storms. The first being a spotty surface hoar layer that sits 30-40 cm down and the mid-November crust buried 90-160 cm deep. Snowpack tests on the crust have shown variable results from sudden to no result. Tracking and monitoring this potentially weak interface is crucial, especially as we move forward into this stormy period where the snowpack will see more load.