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Hurricane Ian is Latest Example of Intensifying Storm Trend

Storm surge on a city street

Hurricane Ian is Latest Example of Intensifying Storm Trend

The cleanup and recovery from Hurricane Ian will be ongoing for weeks, months and perhaps years. The memories of the storm will last much longer.

But scientists fear Hurricane Ian is just the latest example of how ocean waters, heated by climate change are turbocharging hurricanes.

In fact, data from the National Hurricane Center shows that since 2017, 30 Atlantic tropical storms became much more powerful in less than a day.

The phenomenon is known as rapid intensification - getting very strong, very fast.

Hurricane Ian's Path to Category 4

For Hurricane Ian, go back to September 27-28, as the storm moved off the west coast of Cuba and roared towards Florida over the open waters of the northwestern Caribbean and southeastern Gulf of Mexico  to understand the worry.

Early Tuesday morning, Hurricane Ian intensified into a major Category 3 storm, with sustained winds of 125 mph. By Wednesday morning, it had left Cuba and reached Category 4. It was bordering Category 5 by the time it made landfall later in the day.

Hurricane Ian packed two days’ worth of rapid intensification into 36 hours, as it went from a tropical storm with 45 mph winds on Sunday to a Category 3 hurricane by Tuesday.

That’s a 67% strengthening in less than 22 hours.

What is Rapid Intensification?

The U.S. National Hurricane Center defines rapid intensification as an increase in the maximum sustained winds of a tropical cyclone of at least 30 knots (about 35 mph) in a 24 hour period.

"Rapid intensification happens when a tropical cyclone that already has some organization moves over very warm water and within an atmospheric environment of calm surrounding conditions and a moist, unstable air mass," said Richard Knabb, Ph.D., Director of NOAA’s National Hurricane Center. 

It's difficult to predict rapid intensification, especially when it is happening close to landfall.

"However with Ian, all of these factors for rapid intensification were present and anticipated fairly far in advance, which is why warnings were issued that the storm would likely get much stronger,” adds Knabb.

Climate Change Fuels Stronger Storms

But here’s the problem. Warmer water fuels stronger storms and climate change is warming up the oceans.

Hurricane Ian travelled over waters that were about 1.8 degrees Fahrenheit (1 degree Celsius) warmer than normal.

"Warming sea-surface temperatures provide fuel for hurricanes, which also rely on a moist and unstable atmosphere — all of which are becoming more conducive for strengthening hurricanes in our changing climate," said Rick Luettich, Ph.D., Director of the University of North Carolina’s Institute of Marine Sciences in Morehead City. “Recent data shows on average, hurricanes are peaking in strength a bit higher than they used to, and they seem to be intensifying at a rapid rate a bit more frequently."

In addition, storms are sitting longer over areas, doing more damage, and sending more rain and storm surge into communities.

“It’s the water that causes the most damage, the greatest loss of life and is the hardest to recover from,” adds Luettich.

Warmer Ocean Water Is The Problem

More than 90% of global warming over the past 50 years has taken place in the oceans, according to the National Oceanic and Atmospheric Administration. The past five years have been the warmest on record for the world’s oceans.

And much of that warming has happened in the top levels of the ocean where hurricanes get their energy, said Jeff Masters, a meteorologist at Yale Climate Connections.

“Hurricanes are heat engines, which means they take heat energy from the oceans and convert it to the kinetic energy that are winds,” Masters told CNN. “If you increase the amount of heat energy in the ocean by warming it up, you’re going to increase not only the maximum intensity they can get, but also the rate at which they get to that maximum intensity.”

The good news is that doesn’t mean the number of hurricanes each year will increase. However, the proportion of storms that become major storms will increase.

Fortunately, forecasters are getting better at seeing the signs of rapid intensification and can send out warnings earlier. That’s because computer modeling is improving, and meteorologists are more confident using it. It’s also because there have now been enough cases of rapid intensification that such storms are easier to predict.

Learn More

PBS NewsHour

Hurricane Ian causes catastrophic damage in Florida


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