Avalanche Forecast

Low - Due to the number of field observations on Monday

A mix of sun and cloud is expected on Tuesday with light alpine wind from the north and treeline temperatures around -10C. A mix of sun and cloud is also forecast for Wednesday and Thursday. Alpine wind is expected to remain light from the north and treeline temperatures are forecast to remain around -10C.

Over the weekend there were several very concerning large persistent slab avalanches that were human triggered.  At least 10 close calls were reported to us and several of these avalanches involved multiple people being buried.  Three of these avalanches were in the Allen Creek riding area and one was in the Monashees near Blue River.  These avalanches all released on or stepped down to the mid-December weak layer down 1-1.5 m in the snowpack. Check out the MIN posts and a great video on the Frozen Pirate Snow Services Facebook page for more details. Also reported over the weekend were natural storm slab avalanches up to size 3, natural storm slab avalanches stepping down to the mid-Dec layer, and remotely triggered avalanches triggered from up to 100 m away.On Tuesday, the recent storm snow is expected to remain reactive to human triggering in wind loaded terrain and steep unsupported or convex features where buried surface hoar remains reactive. The mid-December weak layer continues to be a real concern for the region and persistent slab avalanches remain possible. It may be possible to trigger this layer in shallow snowpack areas or smaller storm slab avalanches could step down.

40-60 cm of recent storm snow typically overlies the variable mid-January interface which consists wind affected surfaces in exposed terrain, surface hoar up to 7 mm in sheltered areas, and/or widespread faceted old snow. The bond between the new snow and the old surface is generally gaining strength with colder temperatures that followed the storm but weaknesses are lingering, especially where surface hoar is preserved. Strong southwest winds during the storm have redistributed the new snow and developed wind slabs in leeward terrain features. Isolated moderate outflow winds may have more recently resulted in reverse wind loading. The mid-December surface hoar/facet layer lies anywhere from 50 cm down in shallow snowpack areas to 1.5 m down in deeper snowpack areas. This layer woke up during the recent storm and has remained reactive to human triggers several days after the storm ended. Several large human triggered avalanches including events with multiple burials have occurred on this layer over the weekend.