Kootenay Boundary

This bulletin is based on limited data. Local variation in conditions and danger levels are likely to exist. To produce more accurate forecasts, we need information. Please send an email to [email protected].

Poor - Due to limited field observations

The forecast calls for 10-20 cms of snowfall accompanied by moderate easterly winds for thursday night and into friday morning. Freezing levels are expected to remain at or near valley bottom for this period.Unsettled weather will continue for most of friday, but will give way to cold arctic air moving south into the region for saturday and sunday bringing clear skies, light winds and temperatures reaching -15.0 at ridgetop.

While observations are extremely limited at this time, avalanche activity is expected in the wake of wednesday night's system. If more snow and wind arrives as forecast another round of avalanche activity is likely to occur, and the size and likelihood of avalanches in the Kootenay-Boundary will increase as more snow accumulates and winds blow it around. Check the weather forecast section for details on expected timing and intensity of the next system.

I have limited snowpack information for this region. Snowpack depths are likely in the 60-80cm range at about 1600m and about 125cms at 2000m. The following information is an overview of conditions in nearby regions which may provide some insight into what's happening in the Kootenay-Boundary: -Below 1200m or so most areas do not have enough snow to produce avalanches except perhaps in isolated, shady spots where the wind has deposited pockets of deeper snow on smooth terrain. Above 1200m, average snowpack depths range from 90-150cms or so at lower elevations and areas that have less snow, to well over 200cms at upper elevations and in areas that got a bigger dump over the last weekend. -In the upper snowpack, windslab and storm snow instabilities exist within storm snow accumulations of up to 80cms+. These layers were active throughout thursday in many regions and will continue to develop in the Kootenay-Boundary region with forecast weather for thursday night. In the Kootenay-Boundary region watch for the possibility of reverse loading with the forecast easterly winds associated with thursday night's system. The mid-pack may contain a melt-freeze crust in areas that had a warm spell earlier in the season and/or surface hoar. The surface hoar especially was very active last week, but recent reports suggest it may be starting to settle out. Haven't heard much about the crust lately. Some locations reported a rain-soaked layer at the bottom of the new snow that fell over the weekend; we don't know much about this layer but it'll be one to watch in the future as it freezes up-it's a classic setup for a facet-on-crust layer. As far as the deep pack goes, basal facets have been reported in the Lizard Range and the Purcells. This layer is currently very reactive in the Lizard Range. If you are seeing action near the ground in other areas, this is the likely culprit. Most other regions report fairly solid basal layering. There's bound to be variability throughout the region and one slope/mountain/drainage may differ significantly from the next. A conservative approach combined with careful investigation of local conditions is advised until we get a better understanding of conditions. Anticipate increased slab development and avalanche activity with snowfall and wind forecast for thursday night.