Rain may help local reservoirs

By Lethbridge Herald on June 18, 2025.

LETHBRIDGE HERALD

Only one of three major southern Alberta reservoirs has a water level considered to be in the normal range.

As of Tuesday, the St. Mary Reservoir was at 87 per cent capacity according to the Alberta government’s reservoir storage summary.

The Oldman reservoir, at 66 per cent capacity, and the Waterton reservoir, with 69 per cent capacity, were both considered below normal.

The Keho reservoir north of Lethbridge is also considered below normal with 84 per cent capacity. The Milk River reservoir south of Raymond is listed below normal at 82 per cent capacity while the Chin reservoir is in the normal range at 76 per cent capacity. Forty Mile (94 per cent) and Grassy Lake (70 per cent) are also in the normal range.

Payne Lake at 96 per cent is also normal.

There are currently 35 water shortage advisories in place across the  province. While most water basins are at Stage 0 out of 5, the Oldman and Milk River basins are both listed at Stage 3.

The moisture situation could change somewhat later this week with much of southern Alberta forecast to get substantial amounts of rain on Friday and Saturday and possibly into Sunday.

While a 60 per cent change of up to 20 millimetres of rain is forecast Friday for Lethbridge, the city could see between 35-45 mm Saturday and as much as 15 mm on Sunday.

From the Crowsnest Pass – where the potential for snow exists Saturday  – to Taber, varying amounts of moisture are also forecast for those  three days, as well.

Calgary on Saturday could get as much as 50 mm of rain.