Schools are closed and police are warning motorists to be wary of icy and snow-covered roads Monday after a winter storm swept through much of Atlantic Canada overnight.

More than 16,500 customers were without electricity in Nova Scotia early Monday. The Nova Scotia Power website shows power outages along the Bay of Fundy shore to Yarmouth and in Cape Breton.

Spokeswoman Lauren Brown said poor road conditions were slowing efforts to get the electricity back on, especially in the Annapolis Valley and south-western region.

"The conditions in that part of the province are particularly severe overnight and into this morning, so crews are having some challenges getting to some of those areas," she said Monday.

Brown said they have restored power to 14,000 customers, with 12,000 still to go.

All Nova Scotia school boards have cancelled classes.

The CBC's Phonse Jessome says Sunday's rain followed by the overnight snow has made roads around Halifax slippery.

with files from the Canadian Press