The Ottawa airport was on backup power and social media lit up with video and photos of damage from a tornado near the nation’s capital on Friday.
Environment Canada said a severe thunderstorm produced a tornado that tracked over Kilburn, Dunrobin and Gatineau.
WATCH: Video posted to social media on Friday showed dark storm clouds and damage after a storm rolled through the Gatineau and Ottawa areas
The agency said preliminary analysis of the damages marked it as an EF02 tornado, with winds reaching at least 180 km/h.
It caused severe damage to buildings and overturned cars, knocked over trees and hydro poles.
The extreme weather came as a line of thunderstorms tracked across southern Ontario.
Powerful winds and heavy rain were also seen across Quebec.
WATCH: 3 ‘serious’ injuries after tornado touches down in Dunrobin — mayor
One storm intensified at Calabogie, and it showed the “classic radar signature of a tornado” by the time it arrived in Dunrobin.
There were many reports of injuries; several people were hurt critically.
Four patients suffered “serious traumatic” injuries in Ottawa and were being treated on Friday night, according to Ottawa Paramedic Service.
Two others suffered minor injuries and are currently in local hospitals.
WATCH: Gatineau man films video from inside a tornado
The storms knocked out power to as many as 261,000 people in Ontario and Quebec.
Hydro Ottawa said at least 147,000 customers were affected by power outages.
Meanwhile, Hydro-Québec said over 114,000 customers were without power on Saturday morning.
Authorities said on Saturday that it could take days to restore power to Ottawa-area homes due to damage caused to a key Hydro One transformer station.
WATCH: Storm clouds were seen swirling over Gatineau, Quebec on Friday as a tornado touched down in the area
WATCH: Lots of damage left behind after tornado touches down in Dunrobin
Lynne Lessard, deputy press secretary for International Trade Diversification Minister Jim Carr tweeted this video of a storm swirling in Gatineau.
Prime Minister Justin Trudeau asked people to “stay safe and follow the instructions of first responders and check in with people who might need extra help.”
WATCH: Trees uprooted, cars damaged as tornado touches down in Gatineau
“We’re monitoring the situation and thinking of everyone affected.”
Here are some photos from Dunrobin that were taken amid the storm.
This video, taken by Andrew MacKendrick, director of media relations for Health Minister Jane Philpott, showed a tornado blowing through Gatineau.
And this video showed a tornado as the user passed through Dunrobin:
The Professional Paramedic Association of Ottawa said they responded to 16 calls related to a tornado in the Dunrobin area, about 35 kilometres from Ottawa.
The organization said calls concerned people who were trapped in their homes, basements and cars as power lines went down.
This is what damage looked like in Dunrobin.
These videos showed stormy clouds and damage near Gatineau and Ottawa.
These pictures showed power lines down and broader damage in the Greenbank area.
Homes were damaged in the Mont-Bleu area of Gatineau.
Meanwhile, the Ottawa airport was on backup power on Friday.
There were flooded streets in Ottawa’s Glebe neighbourhood.
Here are some photos of the damage that was left in Gatineau.