Ottawa sees more than 100 mm of rain as severe Canada Day storm floods basements

Some residents of Ottawa are dealing with flooded basements and thousands are without power after a severe storm moved through the region on Canada Day.

Severe weather with heavy rain and thunder moved through the region on Wednesday afternoon, with many areas under a yellow alert severe thunderstorm watch as of 3:15 p.m. from Environment Canada.

The storm led to the Canadian government cancelling the evening show portion of its national Canada Day ceremony at LeBreton Flats Park, including the fireworks.

Environment Canada said a few thunderstorms occurred for about four hours, with 118 mm of rain recorded at the Ottawa airport.

Kate Leclerc, meteorologist with Environment Canada, told Global News the Ottawa downpour broke the record for most rain on July 1. The previous record at Ottawa airport was 58.9 mm in 1959.

“That’s how thunderstorms tend to happen, it can be very fast, it can change very rapidly and that’s exactly what happened in the Ottawa area,” Leclerc said.

She said the rain began to fall “real fast” at about 2 p.m. before getting heavier at about 3 p.m. The majority of the rain had fallen by approximately 7 p.m, Leclerc said. There were also winds of about 70 km/h.

In a post on X, Mayor Mark Sutcliffe said ‘record-breaking rainfall” was recorded and caused significant flooding and power outages.

“It happened quickly, it affected communities and homes across our city, it turned a day of celebration into a very difficult and challenging situation for thousands of residents,” Sutcliffe said in a news conference Wednesday afternoon. “We’ve heard that the amount of rainfall was actually higher in certain parts of the city than what was gathered at the airport.

“We believe this was one of the worst flooding events in our city in the last 25 years.”

He said his office is working with municipal staff on measures to assist residents and they have received more than 1,900 service requests for flooded basements through 311.

The city’s general manager, Ryan Perrault, advised the mayor and members of council that the rain has also resulted in basement flooding, according to a message shared by Ottawa Coun. Laura Dudas on Facebook.

Waste collection restrictions in certain neighbourhoods have also been suspended over the next week at Sutcliffe’s request.

The mayor added that those who have experienced flooding or damage to their property can report it on their online 311 portal using their MonServiceOttawa account. He said this recommendation comes as a result of long wait times on the 311 phone line due to an “exceptional volume” of calls.

Sutcliffe told reporters that as various departments were already “in enhanced operations” for Canada Day, they were able to coordinate a response quickly.

Ottawa Police reported several flooding situations on Wednesday afternoon and evening, including closures of some parts of Highway 417. Most closures of the highway have since ended, with the roads reopened. Police said Thursday morning Scott Street between Hinchey Avenue and Stirling Avenue and Moodie Drive south of Carling Avenue remain closed due to flooding.

Dudas said the storm also downed tree branches in several neighbourhoods. She said in a Facebook post that while 311 is receiving numerous calls, if people see a tree or branch that poses immediate danger to report it.

Hydro Ottawa said it was responding to numerous power outages in the city, with about 5,300 people still without power as of 2:10 p.m. Thursday. It says several are currently under investigation, with a time of restoration not yet known. The mayor said about half of these homes should have power restored by the end of thet day.

“Crews are responding to localized outages in flood conditions. For safety, stay 10m away from downed lines and avoid flooded basements,” the Crown corporation said on its website.

Residents are advised that if the water has risen above the level of electrical outlets, baseboard heaters or an electrical panel, they should call Hydro Ottawa to disconnect the power safely.

Ottawa Fire Services reported responding to 700 calls regarding downed wires and electric hazards in flooded basements, Sutcliffe said.

It’s not only the City of Ottawa that was impacted by power outages, as Hydro One says thousands are also dealing with issues, including people in Brockville and Ganonoque.

The city is under another yellow alert severe thunderstorm watch Thursday afternoon, with Environment Canada warning of wind gusts near 100 km/h, rain that could exceed 40 mm, and up to ping-pong ball sized hail. There is also a risk of tornadoes.