Northwest Coastal

Good - -1

Heavy snowfall is expected to begin sometime early Tuesday morning. The Terrace area is forecast to get about 40 cm of snow at treeline combined with strong southwest winds and freezing levels rising to about 800 metres. The freezing level should drop back down to valley bottoms on Wednesday, however the strong winds will continue as another 20 cm of snow falls at treeline. It looks like the snow and wind will continue into Thursday before a ridge of high pressure dries the area out on Friday. The inland areas around Smithers will get the same pulses of precipitation; however some of the punch will have been left behind in the more coastal areas. Expect about 15 cm from the Tuesday storm, and another 10 cm on Wednesday.

Some reports of explosive controlled avalanches up to size 2.0 along the highway corridors. These avalanches are not a good indicator of the problems that skiers and riders face in the backcountry. The load from the new storm may be enough to cause a widespread natural cycle.

The recent storm snow is consolidating into a slab and becoming more reactive in tests. The main concern is windslab. The old windslabs are on south through west aspects, and they are stiff and continue to be easily triggered. New windslabs are building on north through east aspects, making travel a bit tricky; limited options exist for avoiding both types of windslab. Change is coming on Monday night or Tuesday morning, when heavy snowfall and warmer temperatures may overload all of the current weakness. I have left in the paragraph from yesterday because the problems are slow to heal, and I believe they are still valid. The deep snowpack is considered to be well settled with no persistent layers of concern. There is now 30-40 cm of dry cold snow above windslabs that have developed due to strong NE outflow winds which have not bonded to the January 8th surface. These pockets of hard windslab can be triggered by light loads such as a single skier or rider. Some areas have developed surface hoar or surface facetting on sheltered slopes in the alpine and at treeline, that are now getting buried by new snow and shifting winds.