Summer Update on Kootenay Lake Water Levels and Conditions

Kootenay Lake operations have complied with the International Joint Commission's (IJC) 1938 Order of Approval through the spring and summer, with the lake level peak occurring in early June and then decreasing to current levels.

Inflows to Kootenay Lake peaked on May 17. The lake reached its 2024 peak elevation of 1745.67 feet (532.08 meters) on June 4 at Queens Bay, British Columbia. The level peak was close to the 1976-2023 average; however, it occurred about a week earlier than usual.

The Kootenay Lake level then decreased throughout June. During the freshet, lake releases were limited by the natural constriction at Grohman Narrows (shown in the purple line of Figure 1). On June 26, Kootenay Lake at Nelson, British Columbia, dropped below 1743.32 feet (531.36 meters).

Based on the 1938 Order of Approval, Kootenay Lake levels (as measured at Nelson) will be kept below 1743.32 feet until August 31. The control of lake level will fluctuate between Corra Linn Dam (shown in the pink lines of Figure 1) and Grohman Narrows (shown in the purple lines of Figure 1). Starting September 1, the upper limit for Kootenay Lake level will increase to 1,745.32 feet and switch back to the Queens Bay gauge for compliance measurements.

Figure 1: Kootenay Lake levels at Queens Bay (green) and Nelson (orange), lake outflow control by Corra Linn (pink) or Grohman Narrows (purple), and the International Joint Commission 1938 Order of Approval Rule Curve for 2024 (red). Credit: FortisBC (data) and Environment and Climate Change Canada (plot), 2024

Redfish Creek (West Kootenay) and Moyie Mountain (East Kootenay) snow pillow stations saw below-normal snow accumulation (Figure 2) from October to May. Cooler and wetter climatic conditions experienced in May and June have caused the snowpack at higher elevations to persist. Additional snowmelt isn't expected to cause peaks in lake level.

Figure 2: 2024 data from the Redfish Creek and Moyie Mountain snow pillow station. Orange lines illustrate the Snow Water Equivalent (SWE) for the current year. Black line represents the average SWE for the station's periods of record. Credit: BC River Forecast Center (data) and Environment and Climate Change Canada (plot), 2024

Quick Facts

• The International Kootenay Lake Board of Controloversees the operation of Corra Linn Dam to manage water levels in Kootenay Lake.
• This year's board and public meetings were held May 22. A recording of the public meeting is available on Vimeo.
• The web-based Kootenay Lake Visualization Toolis available for the public to investigate Kootenay Lake conditions in dry, normal and wet years.
• You may contact the board through the Contact formon its website.
• Stay in touch and subscribeto receive email news updates from the Kootenay Board.

Contacts

Sonja Michelsen, U.S. Secretary

Martin Suchy, Canadian Secretary

International Kootenay Lake Board of Control

Public link

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