Landowners from Youngstown to the Thousand Islands, still reeling from the worst Lake Ontario flooding on record, are hoping 2020 brings more moderate lake levels.

But the latest forecasts from the International Joint Commission show that by March 2020, the lake is likely to be on par with or higher than it was this past March. 

The IJC uses a probabilistic forecast, projecting high- and low-water extremes that have a 5 percent chance of occurring. Under especially dry conditions, by late March the lake would be at 245 feet — just below the long-term average water level. But if especially wet conditions prevail, as they did in 2017 and this year, the lake would be 247.7 feet — the level at which most landowners begin feeling the effects of high water. 

The forecast also includes a 50 percent "average," meaning there is a 50/50 probability the lake will rise above that projected water level. That "average" is 246 feet by late March — almost exactly where the lake was in March 2019.

Many shoreline residents are worried this forecast could portend yet another year of record-high water.

Jim Shea, president of the Lake Ontario St. Lawrence River Alliance, said that after the record-high water of 2017 and this summer, many lakeshore business-owners are no the brink.

"We’re extremely worried," Shea said. "I’ve talked to half a dozen marinas around the area, and they say if this happens again in 2020, they’re out of business.”

But the IJC says its forecasts do not show that especially high water is likely in 2020.

The lake reached 246 feet in March 2018, and yet last year the lake barely surpassed 247 feet during its May peak. For most of summer 2018, Lake Ontario's level was right about average.

A spokesman for the International Lake Ontario St. Lawrence River Board, an IJC subsidiary that sets lake outflows, said flooding this year and in 2017 largely resulted from conditions that developed later in the spring and summer.

“The events of 2019 were unprecedented, as they were in 2017," said Bryce Carmichael, secretary of the board. “We were basically at the same level in 2018 and we didn’t see flooding.”


Carmichael said the IJC estimates a 28 percent probability that the lake will exceed 247.7 feet at any point next year. “That’s when a lot of people start to see problems — at that (247.7 feet) level," he said.

The IJC cannot predict precipitation six months in advance, but it can estimated what the inflows might be, based off forecasting for the level of Lake Erie. 

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