Ontario's provincial utility says power has been restored to more than half a million customers four days after an ice storm first moved into the region, but that some hard-hit areas may remain without it until the end of the week.

Hundreds of thousands of Hydro One customers are without power after a massive winter storm swept through Ontario, causing widespread damage.

Over 218,000 Ontario homes are in the dark as widespread blackouts impact the province amid a brutal ice storm this weekend, according to Hydro