April 10, 2024
As reported in our water level update last fall, drought conditions across the Shuswap and South Thompson drainages had rebounded from Level 5 in late summer and early fall to Level 3 in November as a result of cooler weather and some fall rain. Shuswap Lake levels were also the lowest recorded in the past 50 years. Lake levels continued to drop through January, remained relatively constant through early February and then started slowly increase resulting from some warmer and wetter weather in late February and the beginning of March. This trend has continued in early April. The generally warmer weather in March has started the low elevation snow melt that has contributed to the lake level increase. As a result, the lake level has increased from the winter low of 344.972 meters to the current level (today) of 345.603 meters as measured at Salmon Arm. This is an increase of 0.731 meters or 2.4 feet.
So, what can we expect through the spring? You will have read in the press or on the internet that, across the BC, snowpack levels are well below average. In their April 10, 2024, update, the Provincial River Forecast Centre reported that measured snowpacks across BC averaged 63% of normal (last year at this time the average was 91% of normal). However, in the South Thompson drainage snowpack dropped from 90% of on March 15 to 79% of normal currently.
Normally there should continue to be some snow accumulation at the high elevation reporting stations through late April and May. However, this should not materially affect the overall average snowpack across the drainage. In the current report, the River Forecast Centre expects the total runoff volume (March through July) to be 90% to 100% of normal (they are expecting a near normal precipitation in the spring and early summer).
This will mean that we should expect a slow increase in the lake level through the spring unless there is a very warm, or wet weather through this period. Even with the just below normal runoff volume, we should expect a lower than average peak water level this spring and early summer with little potential for flooding.
The River Forecast Centre will be updating their report on expected water supply in early and late May and through June. SWOA will be monitoring their reports and forecasts of expected river and lake levels in order to update our members throughout the spring.