Avalanche Forecast

Moderate - Uncertainty is due to the limited number of field observations.

  

FRIDAY NIGHT: Snow; 10-15 cm. / Strong, southwest ridgetop wind / alpine low temperature -7 / Freezing level 800 m.

SATURDAY: Snow; 15-20 cm. / Strong, southwest ridgetop wind / alpine high temperature -4 / Freezing level 1400 m.

SUNDAY: Snow; 15-20 cm. / Moderate, west ridgetop wind / alpine high temperature -5 / Freezing level 1300 m.

MONDAY: Cloudy with flurries; 3-5 cm. / Moderate, south ridgetop wind / alpine high temperature -6 / Freezing level 1000 m.

A natural avalanche cycle is expected to begin Saturday afternoon, travel in avalanche terrain is NOT recommended this weekend.

In some areas a few cm of new snow may overlie small surface hoar or a thin ice crust (noted in the Monashees near Revelstoke and around Galena Pass). Otherwise, the skiff of new snow adds to 30-50 cm of accumulated snow since Christmas day, which overlies a mixture of faceted old surface snow and small surface hoar.  

This predominantly low density snow now forming the upper snowpack is most likely to be reactive in wind affected areas where it has been redistributed and stiffened into a slab. However, the two interfaces discussed above will be important to watch as new snow piles up over the weekend.

Two persistent weak layers buried in early/mid Dec. are now 80 to 150 cm below the surface. The form and distribution of these layers are HIGHLY VARIABLE and have created conditions that can vary significantly from one valley to the next. The first layer down around a metre has been primarily reported as small surface hoar. 

The next layer has been reported as a thin freezing rain crust, surface hoar, or thick rain crust depending on elevation and location. As a result, diligent investigation of the snowpack is required to get a handle on local conditions. Forecast snowfall for the weekend may reignite avalanche activity at these deeply buried interfaces.

• Uncertainty is best managed through conservative terrain choices at this time.
• Be aware of the potential for large avalanches due to the presence of a persistent slab.
• Avoid open slopes and convex rolls at and below treeline where buried surface hoar may be preserved.
• Storm slabs in motion may step down to deeper layers resulting in large avalanches.
• Avoid traveling in runout zones. Avalanches have the potential to run to the valley floor.