Flood warning issued for Ottawa River as levels expected to peak

From Arnprior to Hawkesbury, those along the Ottawa River are being asked to monitor water levels as experts warn that flooding is possible.

The Rideau Valley Conservation Authority (RVCA) issued an updated flood warning on April 20, saying that water levels and flows have increased after days of rain and quick snowmelt.

Major flood levels — which is where some buildings and streets are impacted — exceeded the banks on the weekend between Arnprior and Britannia. Levels are expected to increase over the next day, according to the warning.

“Water levels are currently expected to remain well below historical flood levels on the main stem of the Ottawa River,” the statement reads.

From Britannia to Hawkesbury, minor flood levels were seen over the weekend, which means streets and lawns were impacted but not buildings. However, this area of the river is expected to see major flood levels in the next few days, the authority said.

There are several areas in the nation’s capital that are expected to see impacts as water levels along the Ottawa River are expected to peak late Monday evening or Tuesday.

Constance Bay

The warning notes that the levels are currently at the 10-year flood event level and are believed to be rising by 10 cm from Monday to Tuesday. People should see flooding in low-lying areas, but no impacts to roadways are expected.

Grandview to Britannia 

Levels are set to rise by 15 cm and will result in flooding of areas like backyards and parkland. Most impacts, the conservation authority notes, should be yard-level, and it’s not expected to have huge effects on buildings or roads.

Petrie Island to Cumberland 

Properties and parks in this portion of the river vicinity will see the highest impacts as water levels are expected to climb 15 to 20 cm. Water on roads and in buildings is expected, the warning reads.

City of Clarence-Rockland to Hawkesbury

People are being encouraged to use sandbags and clear debris from downspouts as water levels are expected to rise an additional 10 to 15 cm. Low-lying areas and properties will be impacted by the rising water.

Gatineau flooding already happening

At the peak, the river is forecast to be roughly 30 centimetres higher compared with late last week, Gatineau Mayor Maude Marquis-Bissonnette said in an interview Monday. Emergency teams have been deployed to monitor conditions and support residents, the mayor said, adding that 165 homes are at risk of flooding and 41 streets have been closed.

In Quebec City, a storm surge warning is in effect, with higher-than-normal water levels expected along the St. Lawrence River at high tide.

”The good news is that we don’t have a major system on the way,” said Environment Canada meteorologist Guillaume Perron, speaking on rainfall forecasts for Quebec and Ontario.

In Gatineau, Marquis-Bissonnette explained that hydrometric stations, field data, and aerial surveillance are being used to track river levels, while crews continue door-to-door outreach in vulnerable neighbourhoods. She said the situation remains comparable to 2023 flood levels, referring to the major spring flooding that year used as a recent benchmark for severity and impact.

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Marquis-Bissonnette said the peak is expected either Monday night or Tuesday, after which conditions could stabilize depending on weather patterns.

According to Environment Canada, cooler temperatures in Quebec and limited rainfall in the coming days are expected to ease pressure on river systems. Recent flooding has been driven by a combination of rainfall and rapid snowmelt, Perron said.

“The peak is essentially now or very soon,” Perron said, noting that water levels should begin to gradually decline once inflows decrease.

However, snow remains in higher elevations north of the province, including parts of the Laurentians and Mauricie, said Perron, adding, ”we still have about forty to fifty centimetres of snow; we will need to keep an eye on that when it melts.”

Quebec Premier Christine Fréchette said Sunday during a news conference in St-Eustache, in the Montreal area, that flooding is becoming an “increasingly common occurrence” in the province because of climate change.

This report by The Canadian Press was first published April 20, 2026.

—with files from Eli Ridder in Fredericton and Rianna Lim in Toronto