About 49,000 customers are currently without power in Ontario as an ice storm pummels parts of the province, Hydro One said.

The outages, which are concentrated in central and eastern Ontario, are being caused by tree limbs and branches weighed down by freezing rain that break and fall onto power lines, said spokesperson Tiziana Baccega Rosa.

She said some areas in the province, which are known as water-access only, may be without power for more than 24 hours.

Crews will need to either fly in by helicopter or use boats, which they cannot do until the storm is over, Baccega Rosa said. Affected areas may include parts of Parry Sound and Huntsville.