What made Hurricane Milton a monster storm?

Hurricane Milton in the Gulf of Mexico off the coast of Florida on October 9. Credit: National Oceanic and Atmospheric Administration / AP

Words by ITV News Health and Science Producer Philip Sime

Floridians are well used to hurricanes visiting their shores. Hurricane Milton, however, is particularly unwelcome.

It became one of the most intense hurricanes to develop in the North Atlantic, strengthening at a speed which stunned scientists.

Milton formed as a tropical depression on Saturday and took just 24 hours to strengthen into a category 1 hurricane. It was a further 24 hours before its winds peaked at 180mph, making it a category 5 storm.

On Wednesday evening, just hours before it was due to make landfall on the low-lying Florida coast, the US National Hurricane Center described it as a “catastrophic category 5 hurricane” although it was later downgraded.

Why is Hurricane Milton so powerful?

The rapid intensification seen in the case of Hurricane Milton is the result of something described as a "deadly mixture".

The principal factor is Ocean Heat Content, which describes thermal energy stored in the ocean.

Sea surface temperatures in the Gulf of Mexico, where Milton formed and strengthened, are currently around two degrees warmer than average.

Graph showing the thermal energy stored in the Gulf of Mexico in 2024 (red), compared to the average across the past ten years (blue). Credit: Brian McNoldy / University of Miami 

“That may not sound like very much in terms of temperature of the ocean, but it really is a big deal,” Professor Simon Josey of the UK’s National Oceanography Centre told ITV News.

“The ocean provides most of the energy to the hurricane. So you’ve got this huge reservoir of heat in the ocean which is available to power this incredibly powerful storm."

In addition to the warm waters in the Gulf, winds played a factor too.

“The energy released into the atmosphere is driven by the temperature of the ocean surface and the winds blowing over it,” Professor Josey explained.

“It is a deadly mixture of the two. The fact you have these warm temperatures and the strong winds keeps on fuelling the hurricane,” he said.

A map showing the high sea surface temperatures which fuelled Hurricane Milton's formation. Credit: NASA Earth Observatory

Is climate change playing a role?

Hurricane Milton follows Hurricane Helene, a category 4 storm which made landfall at the end of last month.

Scientists at the World Weather Attribution group work to determine the extent to which climate change influences the intensity and likelihood of extreme weather events.

They found that climate change increased Hurricane Helene’s rainfall by around 10% and intensified its winds by around 11%.

Experts say it will likely be a similar picture with Hurricane Milton, as climate change is intensifying the impacts of hurricanes.

Subscribe free to our weekly newsletter for exclusive and original coverage from ITV News. Direct to your inbox every Friday morning.

It is driving up sea temperatures, which, in turn, increases the intensity of hurricanes forming over them.

It is leading to sea level rise, which results in more severe storm surge events.

And it is creating a warmer atmosphere, which holds more moisture, making rainfall more intense.

“It seems like there are new records every day,” said Dr Helen Hooker, meteorologist at the University of Reading.

“It’s happening very quickly now. I’m worried and I’m surprised too. Even though it’s been expected for years, when you see what’s happening, it’s still shocking."

Want a quick and expert briefing on the biggest news stories? Listen to our latest podcasts to find out What You Need To Know…