Avalanche Forecast

Moderate - Timing, track, or intensity of incoming weather system is uncertain

The next major storm system is expected to reach the region Sunday morning. 15-25cm of new snow is expected by Sunday night in the wettest parts of the region. Alpine winds are expected to be strong to extreme from the south or southwest and freezing levels are forecast to reach around 1000m in the south of the region. The stormy conditions should ease on Monday but light snowfall is expected to continue during the day. Alpine winds should progressively ease to become moderate from south. Freezing levels are expected to hover around 1000m in the south of the region. A weak storm system is currently being forecast for Tuesday.

On Friday, three human-triggered avalanches were reported north of Terrace. A ski-cut produced a size 1.5 on a north aspect at 1300m, a skier accidently triggered a size 1 on a NW aspect at 1400m, and a skier remotely triggered a size 1 from 5m away on a NE aspect at 900m. All three were described as storm slabs 25-30cm thick failing on a layer of surface hoar from January 9th. Also reported on Friday were isolated natural avalanches up to size 2 in the alpine and treeline, as well as loose moist avalanches from steep rocky features below treeline. On Thursday, some small natural avalanches were reported falling out of steep un-skiable terrain northeast of Terrace. North of Stewart one natural avalanche size 3.0 was reported in the alpine on a northwest aspect, and further north and east several remotely triggered avalanches were reported up to size 1.5. On Sunday, natural and human-triggered avalanches are expected as storm snow adds to the slab sitting over a layer of weak surface hoar.

We're dealing with a complex snowpack with multiple buried weak layers in the top meter. The new storm snow will be adding to 15-35cm of recent snow which is now settling into a soft slab that sits above a widespread layer of surface hoar. Wind effect is variable across the region. A few km north of Terrace we have a report of wind pressed powder in the alpine, while east a little ways the alpine was described as hard wind slab. Areas with more wind are expected to have less buried surface hoar problems. Below this you can find up to 3 other distinct buried weak layers of surface hoar, faceted snow, or thin sun crusts. These deeper weak interfaces continue to produce variable results in snowpack tests. Forecast strong to extreme winds from the southwest with new snowfall are excepted to quickly develop new wind slabs on north and east aspects.