While Lake Ontario remains above long-term average, regulated outflows will remain as high as feasible based on river conditions. As a result, residents around Lake St. Lawrence are being warned to expect both extreme high and low water levels this winter, as the Board implements a winter deviation strategy. The strategy aims to take full advantage of all opportunities to safely increase outflows and reduce the impact of future levels on Lake Ontario.
High water levels are anticipated when ice begins forming at critical areas of the St. Lawrence River. When ice begins to form, the International Lake Ontario – St. Lawrence River Board must reduce outflows through Moses-Saunders Dam to help create a stable ice cover on the river. Flow management during ice formation helps prevent ice jams in the St. Lawrence River that can restrict flows and cause local flooding.
As ice formation is completed, outflows can normally be safely increased under the ice. This causes Lake St. Lawrence levels to drop, and this drop is also expected to be greater than normal this winter, as the Board continues to investigate potential opportunities to deviate from Plan 2014 and release higher outflows over the next several months in an attempt to lower the risk of high Lake Ontario levels next spring.
At present, the timing of ice formation remains uncertain, as it depends on both water and air temperatures, which are highly variable from year-to-year.
The Board, in conjunction with its staff, continues to monitor conditions on an ongoing basis. Information on hydrologic conditions, water levels and outflows, including graphics and photos, are available on the Board’s website and posted to the Board’s Facebook page at https://www.facebook.com/InternationalLakeOntarioStLawrenceRiverBoard (English), and more detailed information is available on its website at https://www.ijc.org/en/loslrb.
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