Bomb cyclone's path of destruction on United States' east coast

Rebecca Hollis of New Zealand drags her suitcases in a snowstorm through Times Square on her way to a hotel yesterday. Photo / AP

Fifty-eight million Americans are in the path of a brutal winter storm that has battered the east coast, bringing snow and freezing temperatures the likes of which some cities haven't seen in nearly 30 years.

The harsh conditions have been sparked by a bombogenesis blizzard — or a "bomb cyclone" — which occurs when a sharp drop in atmospheric pressure greatly intensifies a storm.

At least 17 people have died as a result of the severe conditions from Texas to New England, including a 96-year-old woman with dementia who was found frozen in a playground in Michigan wearing only a dressing gown and slippers.

Explosive cyclogenesis off the East Coast

A low pressure system that has been intensifying explosively off the East Coast continues to spread snow and high winds up the mid-Atlantic coast into New England this Thursday afternoon. This is an animation of GOES-16 infrared and visible images showing the entire intensification process through 1pm EST today (Jan. 4, 2018). The storm has brought snowfall as far south as the Florida panhandle. The intense low pressure system is forecast to intensify further today before reaching its peak intensity in the Gulf of Maine by tonight. As it does so, the most intense snow together with high winds will continue to impact coastal mid-Atlantic and southern New England during the day, spreading northeastward into coastal Maine by tonight, leading to blizzard conditions at times. Snow is expected to be less intense farther inland. A few additional inches of snow can be expected today along coastal northern Mid-Atlantic, increasing to 6 to 12 inches across coastal new England, and more than a foot expected over interior Maine before the storm moves rapidly away into southeastern Canada on Friday. Check the latest Storm Summary for the latest snowfall and wind gust reports at http://www.wpc.ncep.noaa.gov/discussions/nfdscc5.html

Posted by NOAA NWS Weather Prediction Center on Thursday, 4 January 2018

Florida's capital Tallahassee received its first snow in nearly three decades on Wednesday, and parts of Georgia and South Carolina received their heaviest falls since the 1980s.

Meanwhile, New York City has been battered with heavy snow and gusty winds that have played havoc with commutes and shut down schools on Thursday.

As much as 20cm (eight inches) of snow was expected to fall across the city.

New York governor Andrew Cuomo declared a state of emergency and urged people not to drive.

A car sits in floodwaters from Boston harbour on Long Wharf in Boston yesterday. Photo / AP

"Unless it is essential for you to be out on the roads, you should not be," Cuomo said.

"It becomes a question of common sense for New Yorkers."

States of emergency have also been declared for Florida, Georgia, North Carolina and Virginia.

The storm is now racing north, causing as many as 3000 flights to be cancelled.

"It's sort of akin to a hurricane travelling up the coast," Weather.US meteorologist Ryan Maue told AP.

A Boston firefighter wades through flood waters from Boston harbour on Long Wharf in Boston as a massive winter storm swept from the Carolinas to Maine yesterday. Photo / AP

WHAT IS A 'BOMB CYCLONE'?

Move over, "polar vortex". We have a new weather-nerd term to get our mittens on.
The term "bomb cyclone" turned up in a story in the Washington Post on Tuesday, which very quickly took on a life of its own on social media.

Despite the explosive terminology, it's not as scary as it sounds.

Based on the technical term "bombogenesis", a bomb cyclone is triggered when a storm's barometric pressure drops by 24 millibars in 24 hours — which greatly strengthens the storm.

The happen as many as 50 times a year, but mostly over the ocean.

A man clears the sidewalk around his home in New Bedford, Massachusetts, as heavy snowfall blankets the region yesterday. Photo / AP

"Bombogenesis is the technical term. Bomb cyclone is a shortened version of it, better for social media," said Mr Maue, who helped popularise "polar vortex" in 2014.

"The actual impacts aren't going to be a bomb at all.

"There's nothing exploding or detonating."

The worst of this storm will stay out to sea, but bitterly cold wind gusts of about 100km/h are likely to be more dramatic than snowfalls as the storm barrels northwards.

"We use the term bomb," University of Oklahoma meteorology professor Jason Furtado told AP. "We know what it means, but I do think it gets a little hyped up."