Environment Canada said a low pressure system was intensifying as it tracked across the Maritimes Sunday. The national weather forecaster had issued snowfall warning for central and northwestern parts of New Brunswick.
Meteorologist Barrie MacKinnon said the snowfall was intensifying throughout the day and would persist until Sunday evening, with as much as 30 centimetres expected in some areas.
"It's certainly the first (snowstorm) and a big one for them," said MacKinnon from Halifax on Sunday. "But tonight we're expecting things to taper off and by tomorrow we'll just be seeing some flurries."
New Brunswick Power said nearly 9,000 customers were without power at one point in Fredericton, Woodstock, St. Stephen, Bouctouche, Miramichi and Sussex.
The New Brunswick government was warning residents to watch for flooding and to postpone non-essential travel.
The low pressure system also prompted wind warnings in southwestern Nova Scotia and in Prince Edward Island, where winds were expected to gust up to 90 kilometres an hour.
Environment Canada said higher than normal water levels and pounding surf were expected on Sunday evening and throughout Monday along the northern coast of P.E.I.