forecaster
Member
The Bella Coola region on the central BC Coast is not a region covered by the Canadian Avalanche Centre’s Public Avalanche Forecasts. However, in the interest of public safety, I pass along some information that was sent to us today.
A warm rain event created a thick rain crust around January 8th. This crust extends from valley bottom up to around 6000ft elevation. Following this warm rain event, there was some additional snowfall then an extended cold period with temperature inversions developing near the end of the cold snap. This cold dry air altered the raincrust and weakened (facetted) the adjacent snow. On January 18 a snowfall gently buried the crust and the weak facet layers.
Over the past days snow accumulations over this layer have been increasing to the point where there is now up to 80 cm of snow laying over a very weak layer. The layer fails when you are digging, walking around, and snow stability tests, produce “very easy" results.
This weak layer hasn't produced any avalanches so far, but over the next few days the forecast is for additional 30-40 cm of snow accompanied by strong westerly winds. This additional load may be enough to produce large avalanches.
This kind of layer can persist for extended periods of time, which is unusual for a maritime climate like Bella Coola. While it remains to be seen if the layer persists, a high degree of caution is advised in this area for the next few days at least and after that until it’s known whether this layer has stabilized.
Consult with knowledgeable locals who know the snowpack in the region to ensure you have the information you need to make educated choices about appropriate terrain.
Karl Klassen – Manager
Public Avalanche Warning Service
Canadian Avalanche Centre
kklassen@avalanche.ca
A warm rain event created a thick rain crust around January 8th. This crust extends from valley bottom up to around 6000ft elevation. Following this warm rain event, there was some additional snowfall then an extended cold period with temperature inversions developing near the end of the cold snap. This cold dry air altered the raincrust and weakened (facetted) the adjacent snow. On January 18 a snowfall gently buried the crust and the weak facet layers.
Over the past days snow accumulations over this layer have been increasing to the point where there is now up to 80 cm of snow laying over a very weak layer. The layer fails when you are digging, walking around, and snow stability tests, produce “very easy" results.
This weak layer hasn't produced any avalanches so far, but over the next few days the forecast is for additional 30-40 cm of snow accompanied by strong westerly winds. This additional load may be enough to produce large avalanches.
This kind of layer can persist for extended periods of time, which is unusual for a maritime climate like Bella Coola. While it remains to be seen if the layer persists, a high degree of caution is advised in this area for the next few days at least and after that until it’s known whether this layer has stabilized.
Consult with knowledgeable locals who know the snowpack in the region to ensure you have the information you need to make educated choices about appropriate terrain.
Karl Klassen – Manager
Public Avalanche Warning Service
Canadian Avalanche Centre
kklassen@avalanche.ca
