Much of Dunrobin, a semi-rural community about 22 miles (35 kilometers) west of downtown Ottawa, remained cordoned off by police.
At one point, more than 200,000 Hydro-Québec and Hydro Ottawa customers were without power.
Canadian Prime Minister Justin Trudeau urged residents to check on neighbors who might need help.
At the same time high winds also battered the region and Ottawa Mayor Jim Watson said it could be days before electricity was fully restored.
The area of Dunrobin in Ottawa was hard hit, with 60 buildings fully or partially destroyed.
Damage from a tornado is seen in Dunrobin, Ontario west of Ottawa on Friday.
Finally, I want to thank my fellow caucus members Merrilee Fullerton, Lisa MacLeod, Steve Clark, Goldie Ghamari and Jeremy Roberts for keeping in touch with me around the clock, and giving me a real sense of what the people of the Ottawa region are facing as the recovery effort gets underway.
One of those patients arrived this morning, the hospital noted.
Mr. Johnson and his partner, Pam Cogan, were at home Friday when the tornado warning sounded on their cellphones. Forget the political stripes, they're out the window. Then they emerged to a changed world.
The roof was sheared off, the second storey of the edifice was open to the sky.
"I asked the mayor, and he felt it's probably best to let the first responders and emergency services do their job, don't distract them", he said.
Amid the devastation, there have been many tales of kindness. More than 3,000 people were fed hot meals on Saturday at a community centre in the suburb or Barrhaven.
Hydro Ottawa crews are working to restore power to affected areas, involving clearing trees, debris and fallen wires. And private companies have donated dumpsters for the disposal of food that is rotting in unpowered refrigerators.
Dunrobin, Ont., resident Alex Carlson says the damage left by Friday's tornado is "catastrophic" but the community will come together.
Hundreds of thousands of people were stranded without power in and around the Canadian capital Ottawa on Saturday after a tornado touched down twice, destroying some houses and ripping the roofs off others.