Some 248,500 homes were without power in Quebec Sunday night as the massive storm churned northward from the eastern U.S., where it caused widespread damage, flooding and at least 21 deaths.
Hydro-Quebec said most of the outages were in the Montreal region, the Eastern Townships and the Quebec City area as the outer fringes of the storm brought heavy rain and gusts to the province. Montreal police reported fallen trees, traffic lights which weren't working and two windows falling from the seventh and 19th floor of a building downtown on Sunday night. Streets were temporarily closed in the immediate area of the falling glass, but police said no one was hurt.
Environment Canada said Irene was still carrying sustained winds of 95 kilometres an hour despite being downgraded from a hurricane and then a tropical storm.
Irene's new post-tropical classification meant heavy rain was expected on the left side of the storm track while strong winds were expected on the right, said hurricane forecaster Stephen Hatt. A hurricane or a tropical storm would have had more symmetrical rainfall around the centre.
Forecasters warned the change in status didn't mean the storm couldn't still pack a punch.
"It can be just as intense and in some cases, when they become post-tropical, they can actually intensify," said Hatt.
Wind warnings remained in effect in much of the Maritimes and rainfall warnings were issued for the Eastern Townships, the Gaspe Peninsula and western New Brunswick.
Chris Fogarty, director of the Canadian Hurricane Centre in Halifax, said Irene was expected to push fully into the region and eastern Quebec late Sunday and into Monday.
He said the heaviest rainfall was expected in Quebec while high winds and pounding surf were more of a concern in Nova Scotia and New Brunswick.
"The heaviest rainfall is occurring in the Quebec region — the Eastern Townships — and with the water levels already particularly high there, that (flooding) is going to be the concern," he said.
Fogarty said rainfall amounts could approach 100 millimetres in some areas.
Environment Canada recorded a gust at 93 km/h in Yarmouth, N.S., on Sunday afternoon and said winds could reach 110 km/h, or close to hurricane-force, in parts of western Nova Scotia and southwestern New Brunswick.
Forecasters warned of potential flooding caused by storm surges around Yarmouth, N.S., late Sunday while high tides Monday in the Bay of Fundy could threaten coastal areas in the Chignecto and Minas basins.
Fogarty said the storm front was so wide that rainfall could affect areas around Montreal and as far west as Ottawa, while high winds would be felt in the St. Lawrence River Valley.
"It is broadly reaching and that's why we want to alert people that this is not like hurricanes where all the high wind is concentrated to the eye. All the windy conditions are well away from it. We're talking several hundred kilometres away from the centre of the storm."
Ontario power utility Hydro One said about 140 workers and support personnel would be sent to Vermont early Monday to help restore power there.
The potential for damage in Canada resulted in governments advising people to exercise caution and be prepared for nasty conditions, especially in coastal areas.
Nova Scotia's Emergency Management Office warned residents that Irene, despite no longer being a hurricane, could still cause damage, flooding and dangerous conditions.
Meanwhile, in New Brunswick, Public Safety Minister Robert Trevors said people shouldn't take the storm lightly.
"We want New Brunswickers to stay prepared," he said. "We still have a time period yet before we're able to relax."
Andy Morton, a spokesman for New Brunswick Emergency Measures Organization, warned that trees were at greater risk of causing damage because they have all their leaves.
"Foliage on trees gives them a larger sail factor, so that means the branches will whip around a lot easier and that can result in tree branches breaking and often impacting power lines or whole trees being uprooted," he said.
NB Power spokeswoman Jessica Gallagher said crews were on standby in case of outages.
Air travel was affected Sunday between Canada and major eastern cities in the U.S., including New York, Boston and Philadelphia.
Several dozen arrivals and departures were cancelled at Toronto's Pearson International Airport and Montreal's Trudeau Airport, while all flights to and from the U.S. were cancelled at Halifax's Stanfield International.
Ferry sailings for Sunday and Monday were cancelled between Digby, N.S., and Saint John, N.B., and motorists were warned to expect crossing restrictions on the Confederation bridge between New Brunswick and Prince Edward Island.
Officials with the Atlantic Canada International Air Show in Summerside, P.E.I., cancelled all air displays Sunday in anticipation of Irene's arrival.
The Canadian Hurricane Centre said it was also monitoring another system, tropical storm Jose, which was southeast of Bermuda late Sunday. It said that storm could bring gale-force winds to Canadian waters Tuesday.
— With files from Kevin Bissett in Fredericton