Avalanche Forecast

THURSDAY NIGHT: Cloudy / Moderate, southeast ridgetop wind / alpine low temperature -8 / Freezing level 500 m.

FRIDAY: Snow; 5-10 cm. / Strong, south ridgetop wind / alpine high temperature -4 / Freezing level 700 m.

SATURDAY: Snow; 3-5 cm and another 10-15 cm overnight. / Strong, south ridgetop wind / alpine high temperature -5 / Freezing level 500 m.

SUNDAY: Snow; 10-20 cm. / Strong, southwest ridgetop wind / alpine high temperature -3 / Freezing level 800 m.

Avalanche activity has been reported continuously since New Year's Day, with widespread natural size 2-3 storm slab avalanches at all elevations. Over this period there have been numerous reports from the Shames area of human triggered avalanches, including some very reactive storm slabs sitting above surface hoar and crust layers. Recent MIN reports show great photos of these avalanches, which at the time released on 30-70 cm deep weak layers. These layers should be roughly 100 cm deep now. Between Christmas and New Year's there were some notable snowmobile triggered avalanches on weak layers in the Nass/Sterling/Beaupre areas, and some very large explosive triggered avalanches on deep weak layers in the northern parts of the region.

As the storm eases off we are concerned about both the recently deposited storm slabs, and these buried weak layers (which vary throughout the region).

A non-stop series of storms has deposited 75 to 150 cm of new snow since New Year's. The amount of snow, as well as the wind speed and direction, has been highly variable between different drainages over this period, so there is uncertainty about exactly what the upper snowpack will look like as we come out of this storm. However lingering storm and wind slabs will likely need a few days to stabilize.

Aside from this new snow, the main concerns vary throughout the region. In the Shames area, this new snow has been bonding poorly to a surface hoar and crust layer that is now an estimated 75-125 cm deep. A bit further north in the Nass/Sterling/Beaupre areas there is potentially still concern about an older weak layer of surface hoar and crust that is now roughly 150 cm deep. In the far north of the region there is concern about weak snow at the bottom of the snowpack. At this point there is some uncertainty about whether these layers will still be reactive after such an intense stormy period.

• Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
• Avoid freshly wind loaded terrain features.
• Be aware of the potential for large avalanches due to the presence of a persistent slab.
• Storm slabs in motion may step down to deeper layers resulting in large avalanches.
• Surface hoar distribution is highly variable. Avoid generalizing your observations.