A man shovels snow at the entrance to federal building in downtown Moncton on Thursday, Jan. 4, 2018.Stephen MacGillivray/The Canadian Press
The massive hurricane-force storm battering Atlantic Canada gathered strength throughout the day and evening Thursday, damaging properties and leaving tens of thousands of Nova Scotians in the dark.
As municipal offices closed early and public transit, including ferry services were shuttered, skepticism over whether early storm warnings were overblown faded, as did questions over why the storm was not simply called a Nor'easter but dubbed instead a "weather bomb."
The storm's rapid intensification, tree-bending winds and low-pressure system made the reason clear as darkness fell across Nova Scotia. "You hear this term 'weather bomb' and it sounds like hype," said Jim Abraham, a former Environment Canada meteorologist, blogger and long-time observer of storms who is based in Halifax. "But it's actually based on science."
Weather bombs are powerful cyclones that draw energy from rapid drops in pressure caused by hot and cold temperatures colliding, Mr. Abraham said. To be classified as a weather bomb, the central pressure of the storm must drop 24 millibars over a 24-hour period. This is according to John Gyakum, the McGill University professor who helped coin the term in a research paper published in 1980.
"From what I can tell, the pressure has dropped in excess of 50 millibars in the last 24 hours," Mr. Abraham said. "That would be double the category for a bomb."
Its victims spent much of Thursday bracing for a continued and wild impact, the worst of which was expected to unfold overnight across Atlantic Canada's four provinces.
Social-media accounts were rife with pictures of torn roofs, fallen scaffolding and flooded streets.
At high tide, the storm surge flooded parts of Halifax's famed waterfront boardwalk, moving a Canada 150 sign and lapping at an ice-cream outlet. Water also poured into an excavation site of a massive hotel/office complex.
Earlier, the surging ocean had swallowed a dock in the city's Dingle Park and flooded the short causeway connecting the nearby Armdale Yacht Club to the mainland.
Nova Scotia Power said it had more than 1,000 people at the ready in what is its biggest prestorm mobilization of personnel and resources on record. It also invited the public to make use of its billing centres, which have been transformed into comfort centres, during daytime hours.
More than 50 departures and arrivals were cancelled at Halifax Stanfield International Airport. Marine Atlantic also cancelled sailings between Nova Scotia and Newfoundland, while Bay Ferries shelved its crossings between Nova Scotia and New Brunswick.
In the United States, several international flights destined for New York were diverted to Toronto. The storm dumped as much as 46 centimetres of snow from the Carolinas to Maine and unleashed hurricane-force winds.
Back in Canada, a storm surge featuring coastal flooding and erosion was forecast for parts of Nova Scotia experiencing high tide during the peak hours of the storm, while blizzard conditions were unfolding in large parts of New Brunswick. Extreme weather warnings were also in place for PEI and Newfoundland and Labrador, where warnings of winds up to 180 kilometres an hour were issued.
"It does have the potential to be quite a historic storm," Mr. Abraham said, adding that weather models began showing signs of it about a week ago. Named "Grayson" by U.S. weather networks, the storm is similar to one that struck Nova Scotia on a disastrous Groundhog Day in 1976. It, too, featured high winds and caused significant damage in coastal communities. "These are events that you might only see once in a decade or once in several decades," Mr. Abraham said, adding that "storms are simply Mother Nature's way of trying to balance the Earth."
Environment Canada meteorologist Ian Hubbard said he expected the worst of the storm to have passed by 8 or 9 a.m. on Friday.
Mr. Abraham said he will not be surprised to wake to news that hundreds of thousands of people are without power. "This storm intensified so quickly that it almost looks like an eye if you look at it on a satellite picture," he said. "You don't see that very often. This one is different enough with respect to the intensity of it that it's worth the alarms that have been rung."
With reports from Greg Keenan and The Canadian Press