It will come as no surprise to East Kootenay residents that the latest snowpack measurement on March 1, 2018 has this area at 120 per cent of normal. Snowpacks in the Okanagan, Similkameen and Boundary regions are even higher; in the 140 per cent area.
In fact all of BC has a higher than normal snowpack except for a few regions in the north. The lowest snowpack is the Stikine area with only 68 per cent of normal.
Interior snowpacks increased by an average of 10 per cent in February as several large storm systems made their way through the province.
The data is collected from 133 snow courses and 78 automated snow weather stations around the province. The data is then averaged for a region, so some areas, like Kimberley, may have a greater amount than the area average. There are three snow pack stations in the East Kootenay — Morrissey Ridge, Moyie Mountain and Floe Lake.
La Niña conditions in the equatorial Pacific Ocean have eased over the past month. The Climate Prediction Centre (CPC) at the U.S. National Weather Service/NOAA is forecasting a high likelihood transitioning to ENSO-neutral conditions into the spring. While La Niña is waning, it is not uncommon for the effects of La Nina to persist several months beyond the period of the defined La Niña event. For example, snow packs in previous La Niña events in British Columbia tended to grow more rapidly than normal through the March and April periods. Province-wide snow basin indices during La Niña years tend to increase by 3-5% over the March 1st to April 1st period, and increase by 5-10% over March 1st to May 1st. While there is still uncertainty over how weather patterns will play out over the next few months, continued increases in snow basin indices into April and May are likely to occur, given this year’s La Niña context.
The outlook is for normal temperatures across the province in the coming days, with cooler and wetter weather in the middle of March.
With high snowpacks comes the risk of seasonal flooding, and snowpacks will continue to accumulate for the next month or so.
But melting snowpacks are only one of the factors in flood risk. Much depends on high temperatures and prolonged rainfall as well.
The next snow bulletin will be released on April 9, 2018.