Warm water fueled amazingly rapid intensification that took Milton from a minimal hurricane to a massive Category 5 in less than 10 hours. It weakened, but quickly bounced back, and when its winds briefly reached 180 mph, its barometric pressure, a key measurement for a storm’s overall strength, was among the lowest recorded in the Gulf of Mexico this late in the year.
Milton’s eastward path through the Gulf is so infrequent the most recent comparable storm was in 1848. Tampa—the most populous metro area in its general path—hasn’t had a direct hit from a major storm in more than 100 years, making this week the worst-case scenario for many experts.
The track “is not unprecedented but it’s quite rare,” said University of Miami hurricane researcher Brian McNoldy. “And of those that did that track, this is by far the most intense.”
But it might be getting less rare, and the U.S. is already on a particularly unlucky streak. When Helene plowed through Florida less than two weeks ago, it was the seventh Category 4 or stronger storm to make landfall in the continental U.S. in eight years. That’s more than triple the average annual rate of such monster landfalls in the U.S. since 1950, according to a data analysis by The Associated Press.
Milton formed in the Bay of Campeche in the southwestern Gulf of Mexico. For awhile, forecasters didn’t give the unstable air mass much of a chance to develop into a tropical storm, let alone a monster hurricane. But once it defied the odds, it took off because of warm water and it managed to avoid high-level cross winds that often decapitate storms, especially in autumn. As Milton neared Florida it hit those winds, called shear, which ate away at its strength, as meteorologists had forecasted.
Warm water fuels hurricanes. It’s crucial that the surface water be at least 79 degrees (26 degrees Celsius) and it helps incredibly when there’s deep warm water.
The water at Milton’s birth and along its path was around 87 degrees (30.5 degrees Celsius). That’s almost 2 degrees (1 degree Celsius) warmer than normal and near record levels, both on the surface and deep, McNoldy said.
“Part of the reason it was so warm is because of global warming,” Vecchi said, though he added that last year’s El Niño—a natural warming of ocean waters that influences weather worldwide—and other natural factors played a role. “Now the storm has a lot more energy to draw on.”
That water became an all-you-can eat buffet for Milton.