The nor'easter is forecast to impact New England and the Middle Atlantic region this weekend, bringing potential coastal flooding, power outages and travel disruption.

Meteorologists predict the storm will undergo bombogenesis - a phenomenon also known as "bomb cyclone" - which happens when a cold air mass collides with a warm air mass, triggering a rapid fall in atmospheric pressure.

US meteorologist Anthony D Torres told Sky News: "These nor'easters happen every year, but the powerful ones like this one happen maybe once or twice a decade. And this particular storm, if it produces more than 70cm of snowfall in Boston, would be the largest snowfall ever observed from a single storm in the Boston metropolitan area."

Airlines had already cancelled more than 5,000 flights scheduled to depart between Friday and Saturday, according to flight-tracking service FlightAware. More than 8,500 flights have been delayed.

More than 90% of Saturday schedules at Boston's Logan Airport and New York's LaGuardia were scrapped, according to FlightAware.

Shoppers rushed to stores on Friday to stock up on food and buy generators and snowblowers ahead of the nor'easter - so named because its winds typically blow from the northeast as it churns up the East Coast.

Warnings to stay home and off the roads

NBC correspondent Chris Pollone in Boston told Sky News that "today is a day to stay home".

"Of course, this area is used to heavy snowfall, but what's going to make it so dangerous is the heavy wind that's coming in blizzard-like conditions," he said.

"They say that people who are on the roads won't be able to see anything, and so they're saying it's really a day to stay in, allow the ploughs to do their work and clear the roads."

Officials from Virginia to Massachusetts have rushed to declare an emergency, imposing parking bans and restricting travel in advance of the snow, which is anticipated to fall as fast as five inches per hour.

• Massachusetts: Governor urging people to stay home, heavy trucks banned from interstate highways, emergency declared, Boston expecting 2ft of snow

• Virginia and Maine: People warned to stay off the roads amid potential white-out conditions

• Rhode Island: Entire state under blizzard warning, all non-emergency road travel banned

• Delaware: Only essential personnel to drive in two of its three counties.

Blizzard warnings

Parts of 10 states have been placed under blizzard warnings.

The National Weather Service said the storm was developing as a low pressure system off the southeast coast and would likely gain in intensity as it moves up the East Coast.

It issued a blizzard warning for the Boston metropolitan area and its nearly 4.9 million residents on Friday.

"Expect whiteout conditions and nearly impossible travel at times. The strong to damaging winds will lead to scattered power outages. Also, significant coastal impacts are possible, including coastal flooding and beach erosion," the weather service said.

Fast-falling snow and high winds

Forecasters said up to two feet of snow could fall across the region - as fast as five inches per hour - along with gusts of 70mph early on Saturday.

Winter storm advisories and warnings have been issued from the Carolinas through Maine, where snow was forecast to continue on Saturday.

Photos on social media showed shoppers crowding into grocery stores and stocking up on essentials ahead of the storm.

New Englanders respond calmly

A number of New Englanders have taken the impending forecast in their stride.

Marc Rudkowski, 28, bought French bread and wine at the Star Market in Cambridge, Massachusetts, along with balloons and toys for his dog, who turned one on Friday.

"He's going to love it," he said. "He's a snow dog."

Meanwhile, Merrick McCormack, 51, in Warwick, Rhode Island, said: "I don't fuss with storms. I know in a couple of days, we're going to be free and clear. No need to panic."

However, there have been some concerns about the ongoing supply chain issues in the region, which have been exacerbated by the pandemic.