Hurricane Florence: What you need to know

Credit: Met Office

Mandatory evacuations are under way in parts of the US, as Hurricane Florence bears down on its east coast.

Millions of Americans are preparing for a potentially catastrophic impact, with the hurricane expected to hit land on Friday.

ITV News weather presenter Lucy Verasamy explains why Florence could be so damaging, and also why we are seeing so many hurricanes at the moment.

  • Why are there so many hurricanes this year?

We've got the key ingredients for hurricanes to form - a sea temperature of 26-27C, moisture laden air and unstable air (thunderstorms) off the east coast of Africa.

After a quiet few years, 2017 saw the formation of 10 named hurricanes - the most active season since 2005 (the year of Hurricane Katrina).

This year we've had five named hurricanes so far - but the season continues into November.

Currently three named storms - Helene, Isaac and Florence - are being monitored by the National Hurricane Centre.

  • Why is Florence taking an unusual track?

Usually storms forming off the east coast of Africa take one of three tracks - across the Caribbean, into the Gulf of Mexico, or sheer the Atlantic side of Florida and skim northwards along the eastern seaboard.

A huge area of High Pressure is currently dominating the mid-Atlantic so the latter path is obstructed - as a result Hurricane Florence is expected to make direct impact with the Carolinas.

  • When will Florence make landfall?

Hurricane Florence is due to make landfall on Friday morning US time. Currently it is a Category 4 storm with sustained winds of 130mph and stronger gusts. The unusually warm waters off the coast could well fuel the storm allowing it to strengthen before it weakens.

Tropical storm force winds will be felt in the south-east of the US by Wednesday night into Thursday.

  • What are the impacts?

As well as hurricane force winds, there'll be a storm surge - a wall of rising water and heavy rain.