We hope that all our members have had a wonderful summer and have been enjoying the fall weather. There has been some light snow on the peaks in the watershed, but winter is not yet upon us.
However, those of you that live on the waterfront, or have visited the lake over the Thanksgiving weekend one feature is very obvious – the water surface elevation of the lake is really quite low. Normally, fall rains through October will have resulted in an increase in the tributary inflow to the lake, resulting in the lake level rising as shown in the attached graph 1(this graph shows the typical increase in water level that occurred in 2012. 2016, 2018, 2020 and 2024). The lake level increases through October and remains elevated over November before dropping through the winter months.
This year, there have not been any significant rain events through September and October to increase tributary inflows and, as such, the lake level has continued to decrease through the fall.
Is this an unusual event? Yes and no. The lake level followed a similar pattern in 2017, 2022 and 2024 (See graph 2). What is unusual is the lake level elevation at this time of the year. Looking at some of the Water Survey of Canada for the outflow from the lake to the South Thompson River (which is directly correlated with the Shuswap Lake level, the lake level is near an all- time low for this time of year. Other data indicates that it is approaching a record low for October. The River Forecast Centre’s 10 day prediction is for a change in the trend with the forecasted precipitation in the watershed but is a relatively small increase (approximately 0.1 m (2.5 inches)).
SWOA will keep monitoring these forecasts over the next month and if there are any major changes, report back to you.
