The Province has issued its May 15 Snow Survey and Water Supply Bulletin. The snow basin index for the South Thompson basis remains above normal (110%) for this time of year. Review of the snow pillow data (click here) shows that the melt of the high elevation snow pack in the northern part of the watershed (Celista Station) is well underway while in the southern part of the basin (Park Mountain and Enderby stations) has yet to get underway (these latter stations are at a slightly higher elevation). This means that there is still a substantial quantity of water in the mountains surrounding the lakes and, as indicated in the Province’s Bulletin, there remains a risk of flooding due to snow melt and/or heavy rainfall.
In the past week Shuswap lake levels have continued to increase steadily with the warmer weather, combined with some rain, rapidly melting the mid-level snow pack. Shuswap Lake water levels have increased 0.69 m (2.26 ft.) since our last report. Based on the Province’s forecast of the increase in flow in the South Thompson River, we expect lake levels to continue to rise a further 0.56 m (1.8 ft) over the next 10 days. The current rate of lake level increase continues to track the water level rise experienced in 2012 although the timing is earlier than occurred in that year. If this trend continues we would expect the lake to peak in the second week of June.
We are monitoring this information as it is released by the Province and will provide you with a weekly update or more frequently if there is a substantive change in the projections.