Hydro One says tens of thousands of its customers have lost power after strong winds tore across most of southern Ontario on Saturday.
The utility says more than 21,000 customers are without power as of 10:30 p.m.
The outages stretch from just outside Ottawa to Pembroke, Parry Sound and Kingston and are scattered across the Greater Toronto and Hamilton Area to parts of Niagara and westward to just outside Windsor.
The utility says the majority of the outages will be restored overnight.
Environment Canada has issued wind warnings for areas including Kingston, Prince Edward, Niagara, Hamilton, London, Middlesex, Chatham-Kent and Windsor.
The federal agency says affected areas will experience strong southwesterly winds gusting up to 90 or 100 km/h beginning Saturday evening.