Damage from a tornado in west end Ottawa, ON, 22 Sept 2018 (Instagram)
Environment Canada has confirmed two powerful tornadoes ripped through west end Ottawa before touching down again in Gatineau across the Ottawa River.
Officials say dozens were hurt and at least two residents are in hospital with critical injuries.
Tens of thousands were left without power after at least 80 utility poles either snapped or were damaged.
Meteorologists say severe thunderstorms spawned one twister classified as an EF-3 with winds up to 265 km/h while another tornado was an EF-2 with winds up to 220 km/h.
Tornadoes are not uncommon in Southern Ontario but storms of this strength are rare.
An intense low pressure system which absorbed the remnants of Tropical Storm Philippe unleashed its fury on Ontario, Quebec and the Maritimes after racing through the Northeastern United States.
Environment Canada reports more than 100 mm of rain (a month’s worth) fell in Ottawa turning some streets into rivers in the National Capital (2017 is now its wettest year ever) and neighbouring Gatineau.
Strong winds gusted to 93 km/h at Ile d’Orleans with rainfall amounts of up to 90 mm across Southern Quebec.
Western New Brunswick felt the brunt of this storm in the Maritimes while Greater Moncton recorded 25 mm of rain and a peak wind gust of 69 km/h.
Flooding in Gatineau, Quebec, 06 May 2017 (Instagram)
Days of rainy weather in southern Quebec and eastern Ontario have taken a toll on the region and Canadian soldiers have been asked to help.
High water levels have threatened hundreds of homes and at least 700 residents have been evacuated.
Ile-Bizard, west of Montreal, has been especially hard hit with sand bags helping to keep back rising water in some areas.
In New Brunswick, a low pressure system could bring 50-100 mm of rain to western areas of the province where rivers are already full of water this weekend.