Can US hurricanes like Milton affect the weather in Britain?

Hurricane Milton marched across central Florida on Thursday, whipping up deadly tornadoes, destroying homes and knocking out power to millions of homes.

But as residents in the US prepare for the worst, people in Britain may be wondering whether Milton could impact UK shores. And while there will be no 'direct' impact of the hurricane, there can be occasions where such severe weather events do have an indirect impact.

Hurricanes are a tropical phenomenon driven by warm sea surface temperatures that form far away from the UK. But the giant storms they whip in the Atlantic can impact the weather in the UK, with ‘ex-hurricanes’ sometimes reaching our shores.

What is a hurricane?

Hurricanes, which are known as typhoons in other parts of the world, are powerful tropical weather systems with winds higher than 74 mph.

They form over warm ocean water and cause devastation when they make landfall.

In addition to high winds, they pose a danger due to 'storm surges', where sea levels rise quickly and rush rapidly onto the land causing fast-moving flash floods. Storm surges of just a few feet can be extremely deadly as debris is carried through the fast moving water and can knock people down, damage buildings and disable cars. Some areas expected to be hit by Milton are predicting storm surges of over 10ft.

Can US hurricanes affect British weather?

Hurricanes in the US can affect the weather in the UK, with storms associated with hurricanes causing wind and rain in Britain - but they do not cause the same devastation as seen in the US.

Met Office Deputy Chief Meteorologist Adam Thornhill said: "Hurricanes that affect North America often play a role in the UK’s weather when they move into the North Atlantic.”

Hurricanes typically weaken when they cross the Atlantic, but can still cause rain and heavy winds in the UK.

"The hurricane season in the Tropical North Atlantic frequently plays a role in dictating the state of play with the UK’s dominant weather patterns," the Met Office said in a 2021 blog post rebutting misinformation around Hurricane Larry.

Earlier this month, forecasters warned that storms associated with Hurricane Kirk could affect Britain.

Chris Bulmer, deputy chief meteorologist at the Met Office, said: “Kirk over the North Atlantic will lose its status as a hurricane early next week before being swept towards northwest Europe.

Hurricane Kirk is forecast to cause strong winds in France and the Bay of Biscay, where ferry services will be disrupted. There will also be rain across France, Belgium, the Netherlands and Germany.

The bad weather is currently expected to largely 'miss' Britain, according to the most recent Met Office forecasts.

It is still too early in Milton's lifecycle to predict if it will have an impact on the UK's weather as these storms are extremely hard to plot more than a few days in the future.

Can hurricanes reach Britain?

By definition, hurricanes cannot form over the US.

Hurricanes are tropical cyclones with wind speeds of more than 74 mph but only form over warm tropical or subtropical water closer to the equator. The UK is far too northern with its nearby waters too cool to let storms on the scale of a hurricane to form.

Hurricanes typically lose their strength as they cross the Atlantic, and are traditionally known as ‘ex-hurricanes’.

What happens to hurricanes after they hit the US?

Tropical storms interact with the jet stream and can move towards Britain or mainland Europe.

During their travel across the Atlantic, they can lose their warm core, in a process known as 'extratropical transition.'

But weather including rain and high winds can reach Britain, although typically without the devastating power of American hurricanes.

Professor John Methven of the University of Reading wrote in a 2016 blog post: It may seem bizarre that processes occurring within clouds near the USA, involving tiny ice crystals and water droplets, can have an influence on high-impact weather events thousands of kilometres away in Europe, and our ability to predict them days in advance.

"However, this is the fundamental nature of the atmosphere as a chaotic dynamical system."