Simon Racicot, director of production and maintenance with Hydro-Quebec, told reporters the dam at Chute Bell was built to withstand what he called a millennial flood.
Making things worse is a special weather statement issued by Environment Canada for much of the nation’s capital calling for “significant rainfall” on Friday. The national weather watcher says rain, heavy at times, will move into the area Thursday night and and continue into Friday evening. Total rainfall amounts of 20 to 35 millimetres are forecast to fall by Saturday morning.
"That means a flood that happens every 1,000 years," Racicot said. Hydro workers discovered earlier in the day the millennial level of water had been reached.
"We are confident that the structure is solid," Racicot said. "But the protocols force us to warn people of the danger. We are entering into an unknown zone right now — completely unknown."
The largely rural section of river affected is in Quebecs Lower Laurentians region, about 140 kilometres west of Montreal, stretching about 18 kilometres south to the Ottawa River.
Public Security Minister Genevieve Guilbault told reporters Thursday evening the provinces hydro utility is confident the dam can hold back its current water reservoir and is structurally sound.
“Yes, we expect a second peak,” Michael Sarich, senior water resources engineer with the Ottawa River Regulation Planning Board, said in an interview Tuesday. “But unfortunately we can’t predict what that will look like. We know we have a lot of snow in the northern regions and it’s just beginning to melt.
"But we are expecting more rain over the coming hours and days, so the water levels of the Rouge River can rise," she said in Montreal.
Guilbault said there are 23 residences and 38 cottages in the evacuation zone along the river. Quebec provincial police tweeted they were helping about 250 people get clear of the affected area as a preventive measure.
“I can say with certainty that the flooding situation has changed almost in a blink of an eye,” Kanellakos said. “The number of requests for help is increasing and the flooding threat is imminent. We are reaching our capacity in terms of enabling to deal with the service requests from our residents.”
Hydro-Quebec said through social media that if the dam breaks, the water flow would have minimal impact on locations downstream once it joined with the Ottawa River.
The dam failure alert was to be maintained until 11:45 p.m. Thursday, according to the Quebec public security website.
Residents who need help on their properties to prepare for the expected flooding are asked to call 211 or phone 1-877-761-9076 to get in touch Team Rubicon Canada and Ottawa Volunteer Search and Rescue (OVSAR). Both organizations are prepared to to help residents prepare sandbag walls or to help with cleanup.
Quebec Premier Francois Legault tweeted that those at risk had been advised and provincial authorities are keeping close tabs on the situation.
The warning comes as many parts of Quebec have been hit by flooding. Officials say the flood risk remains high because of a combination of precipitation in the forecast and melting snow to the north.
Earlier on Thursday, Guilbault toured the Lachute area, northwest of Montreal, where flood waters on the Riviere du Nord have risen in recent days.
She said she was impressed with the level of preparation in smaller communities and was satisfied that the number of people on the ground working on flood relief — which includes nearly 1,000 Canadian soldiers — was sufficient.
Quebec public security officials said more than 2,500 homes were flooded and more than 2,100 were isolated Thursday, meaning they were considered cut off due to washed out roads or landslides.
In Montreal, officials raised the security level and increased the number of teams on the ground amid fears flooding could get worse in the coming days but stressed the situation was under control.
"Youre going to see more firefighters, youre going to see more police officers and more municipal workers to help for floods that could come this weekend," said Martin Guilbault, operations chief of the Montreal fire department.
Mayor Valerie Plante warned that anyone who was flooded in 2017 should prepare their homes for more flooding — and possible evacuation — if they havent done so.
"The threat is actually very concrete and direct and this is the message we want to send the entire population," she said.
At a press conference Thursday evening, Public Security Minister Geneviève Guilbault confirmed the evacuation of 23 principal residences and 38 cottages in Grenville-sur-la-Rouge.
Environment Canada issued a rainfall warning for Montreal with 30 to 50 millimetres expected Friday and Saturday.
Rain is expected to begin southern Quebec midday Friday and intensify overnight, spreading eastward.
Nous avons confiance que les installations pourront résister, mais lévacuation du secteur a été recommandée par mesure de précaution. pic.twitter.com/msgXSqQi7D
In Ottawa, Mayor Jim Watson declared a state of emergency Thursday afternoon, calling in the Canadian Forces to help with flood protection.
Michelle Belanger wades through floodwaters Wednesday, April 24, 2019 in Laval, Que. (THE CANADIAN PRESS/Ryan Remiorz)
The City of Ottawa has declared a state of emergency as river levels continue to rise, threatening to surpass those reached when flooding devastated some neighbourhoods two years ago.
We can no longer do it alone.- Ottawa Mayor Jim WatsonEnvironment Canada has issued a special weather statement predicting up to 35 millimetres of rain by Saturday morning, and river authorities are now forecasting that in some areas, the water could rise up to 11 centimetres above peak levels reached in May 2017.
Watson said he's also asked for help from the Canadian Armed Forces, and has been told 400 troops will be deployed to key areas.
"We can no longer do it alone," Watson said. "We are now beyond our city's capacity, and that is why we have called in the Armed Forces."
City manager Steve Kanellakos said the city felt prepared until the latest forecast from Environment Canada.
"I can say with certainty that the flooding situation has changed almost in the blink of an eye," he said.
"I cannot tell you how long we will be in this state of emergency. If the flooding is severe there could be weeks of recovery operations."
Premier Doug Ford has also pledged the provincial government's support, and will visit the region on Friday.
While levels on the Rideau River have stabilized, the Ottawa River is expected to rise about half a metre from Constance Bay to east of Cumberland by the weekend, according to South Nation Conservation.
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