New England is hunkering down before a weekend nor'easter that is expected cause near-hurricane-force winds, fast-falling snow and whiteout conditions, bringing life to a standstill for millions of Americans and Canadians.

Nor-easters are huge storms that form along the East Coast of North America. They get their name from the frigid winds blowing across the coastal area that originate from the north-east.

Across the vast region, thousands of flights have been cancelled and electricity companies are warning of power cuts as trees will likely be blown on to power lines. Crews were being brought in from other parts of the country on Friday to help cope with what could be some of the worst weather in years.

“Trucks are fully stocked, gassed up and ready to go for hundreds of mutual aid line-workers from Michigan and Florida,” said Eversource, an electric company serving Massachusetts.

“They flew in this morning to help repair any damage Saturday’s nor’easter may bring.”

Drivers were urged to stay off roads amid fears the nor'easter could develop into a powerful “bomb cyclone” blizzard.

“With a serious storm expected to bring several inches of snow and strong winds across certain parts of Maine, I encourage people to be cautious and careful and to avoid driving if at all possible,” Maine Governor Janet Mills said.

In New Jersey, Governor Phil Murphy declared a state of emergency.

The nor’easter is almost certain to intensify so rapidly that it will meet the definition of a bomb cyclone as it roars north.

The technical term is “bombogenesis”, which is when the central pressure of a storm, a measure of its power, drops by at least 24 millibars in 24 hours.

The key ingredient of a weather bomb is the collision of cooler air with much warmer air, and that appears to be what will happen.

A cold front from Canada dropped temperatures to a low of minus 8°C in New York City’s Central Park overnight Wednesday into Thursday, while in the Atlantic Ocean, the water is warmer than normal.

Residents were told to keep their mobile phones charged and urged to prepare an emergency kit including water, batteries and dried food.

There were gaps in area supermarket shelves as people stocked up. Noodles and tinned soups were in short supply.

Maine’s Emergency Management Agency advised residents to have three days of food and water in stock to tide them over the storm and the aftermath.

With extensive power cuts expected, households were urged to have a carbon monoxide alarm in place, especially if using free-standing heating devices.

As Maine’s population is among the oldest in the country, officials advised caution while snow shovelling to avoid the risk of a heart attack because of overexertion.

Many nor'easters have made the history books and have caused billions of dollars in damage.

The notorious blizzard of 1888 brought between 100 and 130 centimetres of snow to parts of the country.

It immobilised East Coast cities and killed more than 400 people. The so-called Superstorm of 1993 ranks among the deadliest and most costly weather events of the 20th century. It brought misery from Florida to Maine, killing more than 100 people and leaving millions without power.

Heavy snow and strong winds were forecasted to begin in parts of the Carolinas and Appalachia on Friday evening, the National Weather Service service reported.

The system will then intensify as a nor’easter off the East Coast and bring similar conditions farther north on Saturday, with localised snowfall totals of up to 51 centimetres, the weather service said.

Officials also said windblown snow could make travel “nearly impossible".

Aside from flight cancellations, the storm will most likely lead to reductions in commuter and long-distance train schedules.

The National Weather Service has issued winter storm warnings and storm watches from North Carolina to Maine, and offshore ships are being warned of high winds and waves up to 2.75 metres.

The worst of the storm should hit east of Interstate 95, a major US motorway that links Maine to Florida and passes through many of the corridor’s largest cities.

“It could be an all-out, classic blizzard for New England,” said Paul Walker, a meteorologist with commercial forecaster AccuWeather. “Eastern Long Island up into New England will be taking the brunt of the storm. The question mark remains how far west the good snow goes; will it be back to New York or Philadelphia?”

Agencies contributed to this report