Environment Canada is warning of the risk of tornadoes in eastern Ontario and western Quebec as a thunderstorm system moves through the region.
Tornado warnings were issued for a dozen communities in Ontario, including south Ottawa, Cornwall and Sharbot Lake, but as of 4:30 p.m. the warnings had ended.
However, many communities remain under a tornado watch.
Warnings had also been issued for the western Quebec communities of Huntingdon and Hemmingford but were later lifted.
Environment Canada said severe thunderstorms likely producing tornadoes were imminent or occurring in the area and large hail, damaging winds and heavy rainfall may also accompany these storms.
Emergency management Ontario recommends taking cover immediately when threatening weather approaches.
High winds during the storm knocked down 10 hydro poles on Route 500 near Casselman, Ont., leaving about 6,000 homes without power.
Ontario Provincial Police said there have been no reported injuries or fires as a result of the downed hydro poles.