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Shoreline hazard warning in effect for Lake Ontario as water levels rise

Last Updated Apr 30, 2019 at 6:40 pm EST

The Toronto and Region Conservation Authority (TRCA) has issued a shoreline hazard warning for areas along Lake Ontario as water levels are projected to continue rising until late May or early June.

When the Toronto Islands flooded in 2017, water levels in Lake Ontario reached a peak of 75.93 metres, the TRCA said. The current water level is approaching 75.5 metres.

Making matters worse, high wind gusts of up to 60 km/h are expected to produce offshore waves reaching two metres on Wednesday.

The rising water levels could contribute to erosion along the Lake Ontario shorelines and waterfront communities could experience flooding.

“Properties along the shoreline and the Toronto Islands which experienced flooding during the 2017 event could begin to experience flood impacts as the water level in Lake Ontario continues to rise. Wave action from southwesterly or easterly wind directions could exacerbate erosion and flooding impacts,” the TRCA said.

“Whether or not we are going to see levels like 2017 really depends on how things play out in terms of rainfall over the next couple of weeks,” said Rehana Rajabali, Flood Risk Management, TRCA.

“The thing to remember about lake levels is that they are going to rise sharply, but it isn’t a matter of hours. It’s a matter of days and weeks…so it is a slow burn event and we are going to be entering this period for a prolonged period of time.”

CityNews meteorologist Adam Stiles noted some of complexities that affect Lake Ontario’s water levels.

“Monitoring the rising water levels on Lake Ontario is a regional issue. All of the precipitation that falls in the Great Lakes eventually ends up here, as Lake Ontario is the last stop,” he said. “In addition to the Great Lakes region, you always have to take into account the flooding and water levels on the Ottawa and St. Lawrence rivers. With widespread flooding already occurring along those areas, the release of water out of Lake Ontario is controlled by the dam in Cornwall to also take into consideration the flooding that is occurring.

“Recently the amount of water leaving Lake Ontario has been reduced significantly in order to protect communities downstream of the control point. This resulted in sharp increase in water levels on the lake.”


Flooding has impacted several Ontario communities, including parts of cottage country. Bracebridge, Muskoka Lakes Township, Minden Hills and Huntsville have all declared states of emergency as water levels soared to record highs.

In eastern Ontario, where residents in and around Ottawa area were also dealing with flood conditions, the provincial government said it was activating disaster recovery assistance for both Renfrew County and the city of Pembroke, Ont.

At the opposite end of the province, the Essex Region Conservation Authority issued a flood warning for the municipality of Leamington along with residents living along the Lake Erie, Lake St. Clair and Detroit River shorelines.