CORNWALL, Ont. - A blast of winter-type weather has caused widespread power outages across eastern Ontario.

Hydro One says close to 20,000 customers are without power from Brockville to Vankleek Hill.

Al Manchee of Hydro One says crews will be restoring power all day but it's difficult to say when everyone will have their power back.

He says restoration is a labour intensive process because much of the distribution system is in "rural, off-road inaccesible locations."

About 15 centimetres of heavy, wet snow had fallen on the Cornwall, Ont., area by about 6 a.m. The snow has stopped, but a strong wind is buffeting the region.

The temperature is hovering around zero and icy patches have formed on highways where vehicles have packed down the snow. Ontario provincial police reported dozens of vehicles sliding off the roads. No serious injuries were reported.