Storms of Florence’s scope, with winds of upwards of 130mph, are rare so far north in the US – and its origins are unusual, too

The US may have suffered its most costly year for hurricane damages last year but Florence, the first major storm of the 2018 hurricane season, represents an unusual sort of threat to coastal communities.

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More than 1.5 million peoplehave been told to evacuate Virginia and the Carolinas ahead of the expected landfall of Hurricane Florence, which has strengthened to a category 4 event that the National Weather Service has said is “the storm of a lifetime” and Roy Cooper, North Carolina governor, more bluntly called “a monster”. Donald Trump said it will be “tremendously wet”.

Storms have previously battered North and South Carolina – Hurricane Hugo in 1989 was particularly severe – but storms of Florence’s scope, with winds of upwards of 130mph, are rare in this region. If it follows its most likely track, Florence will be the first major storm to make landfall so far north in the US.

The origins of Florence are unusual, too. “Florence developed further north and east in the Atlantic than you’d expect for a storm that reaches the US,” said Chris Davis, senior scientist at the US National Center for Atmospheric Research. “Storms like that don’t usually make it that far west. But it’s moving at a steady clip and bearing down on some pretty vulnerable parts of North Carolina.”

It’s also notable that there are three hurricanes, including Florence, lined up in the Atlantic at the same time. This echoes 2017, when three huge hurricanes – Irma, Harvey and Maria – tore into Florida, Texas and Puerto Rico, respectively.

Florence will likely raise further questions over the role of climate change, given the increase in fierce, prolonged Atlantic hurricanes in recent years. Warm oceans and a moisture-laden atmosphere are known to fuel storms.

“The primary fuel for hurricanes is a warm sea surface, which is getting warmer with climate change,” said Dr Kelly McCusker, a climate scientist at the independent economic research firm Rhodium Group. “While we can’t attribute this hurricane solely to climate change, we do expect these types of intense hurricanes to happen more often as the world warms.”

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Isaac Ginis, a hurricane expert at the University of Rhode Island’s Graduate School of Oceanography, said that with rising temperatures, hurricanes are likely to become more intense, bring more rain and pose more risks to coastal areas from higher seas and bigger storm surges and waves.

In the case of Hurricane Harvey last year, human-caused warming was found to have made the storm’s record-breaking rainfall three times more likely and 15% more intense.

Hurricane Florence has developed into a major storm over extremely warm water, Ginis said.

“That’s not necessarily connected to global warming, but that’s an indication of what we might see in the future more often,” he said.

Florence is forecast to bring storm surge of up to 13ft before slowing down and dumping a large amount of rain upon the heads of those who haven’t fled. “You will have a compounding effect of storm surge and the waves that will probably be quite devastating to the coastal communities,” Ginis said.

“I just hope that people will not decide to write off the storm, and that’s the most important thing to save peoples’s lives. Nobody can survive with a water level of 3.5 meters.”

Florence may well have occurred without rising global temperatures but in any case it is an archetypal representation of climate change – a damaging, jolting shock to communities that haven’t experienced such an event before.