WASHINGTON, D.C. – International water regulators said Tuesday mild temperatures in the region have allowed “unprecedented” outflows from Lake Ontario.
The International Joint Commission (IJC) — the bi-national organization that oversees shared waterways between the U.S. and Canada — on Tuesday said Lake Ontario outflows through the Moses-Saunders Dam have been “higher than has ever previously been released in the winter” over the past several days. Tuesday’s announcement comes as local, state and federal officials continue to press water regulators to take action to limit the potential for shoreline flooding next year, and call for a review of the IJC’s policies.
Lake Ontario water levels reached a more than 100-year high of 249.08 feet in June, surpassing the previous record of 248.95 feet set in May 2017. Water levels on Lake Ontario have remained above the long-term average for more than a year, last dipping below the average Oct. 31, 2018, according to data from the International Lake Ontario-St. Lawrence River Board (LOSLRB).
The most recent data from Jan. 7 shows the Lake Ontario water level at 246.03 feet, or about 18 inches above average for this time of year.
Water regulators have previously said outflows would continue to deviate from the much-maligned Plan 2014, which would typically dictate outflows from Lake Ontario, including when water levels fall below the trigger points that typically authorize regulators to depart from the water management plan.
Officials said the closure of the St. Lawrence Seaway, which typically extends from late March to late December, and mild temperatures across the Lake Ontario basin have allowed the International Lake Ontario - St. Lawrence River Board (LOSLRB) to set Lake Ontario outflows as high as 377,900 cubic feet per second (cfs).
The 377,900 cfs outflows are in line with the highest recorded outflows of 2019, experienced between mid-June and late-August when Lake Ontario was at or near its highest point in more than 100 years.
“These very high outflows are only possible under the current conditions and may only continue during a relatively short window before temperatures fall and ice formation resumes” the IJC said in a statement, noting at that time outflows may need to be reduced to avoid disrupting the ice cover. “Outflows will be increased again as much and as soon as possible.”
LOSLRB officials said outflows would continue to be set “as high as possible based on changing conditions throughout the basin.” Conditions that could impact outflows include ice formation in the St. Lawrence River, water level differences upstream and downstream of the Moses-Saunders Dam and high water levels downstream of the dam.
Officials said over the next several weeks, regulated outflows would remain “as high as feasible” based on river conditions, and warned residents around Lake St. Lawrence to expect both extreme high and low water levels this winter.
LOSLRB’s winter deviation strategy aims to take full advantage of all opportunities to safely maintain maximum possible outflows and reduce the probability of high water conditions occurring this year on Lake Ontario, the board said in a Wednesday press release.