Many hurricanes slowly gain strength as they move across the open ocean, but a series of recent hurricanes have grown from tropical storms with astonishing speed.
In just one day, Hurricane Milton went from being a tropical storm to a Category 5 hurricane (the highest threshold), with winds that doubled their speed until reaching 257 kilometers per hour. It retreated into a Category 3 storm upon making landfall in Florida.
Meteorologists call that type of dramatic change “rapid intensification.” and they say climate change appears to be making the effect more common.
How common is rapid escalation?
The technical definition, according to the National Oceanic and Atmospheric Administration, is when a hurricane’s winds increase by 35 mph or more in 24 hours or less. Multiple studies have shown that rapid intensification has become more common over the past three decades, causing large storms to become even stronger.
This has happened with some of the most devastating storms to hit the North American coasts in recent years. In 2023, for example, Hurricane Otis became a Category 5 storm as it approached Acapulco, on Mexico’s Pacific coast, killing at least 52 people. In 2022, Hurricane Ian experienced rapid intensification before hitting first Cuba and then Florida, killing more than 150 people and causing $112 billion in damage.
A similar pattern occurred with Hurricanes Helene and Milton in late September and early October, both rapidly gaining strength as they passed over unusually warm seas in the Gulf of Mexico. Milton’s winds peaked at 290 km/h, making it the world’s strongest storm of 2024 at the time.
What is the impact?
The most important thing to know is that the element of surprise can be deadly and costly. Hurricanes that gain strength quickly are more likely to catch people off guard, with catastrophic consequences. When Hurricane Laura went from a Category 1 storm to a Category 4 storm in less than 24 hours in 2020, its storm surge projections increased from 3.4 meters to 6 meters; Some Louisianans who wanted to ride out a weaker storm were forced to make a last-minute decision to evacuate. In 2015, 33 crew members of a cargo ship called El Faro drowned after putting to sea based on forecasts of a weak tropical storm, only for it to become a Category 4 giant in less than 24 hours.
What is causing the change?
The reason hurricanes are getting more powerful and faster is no secret: warmer ocean water. Warmer water produces more water vapor, which provides fuel for storms; Warmer air can also hold more water vapor, which can lead to heavier rain during storms. Higher sea surface temperatures can also intensify wind speeds. “It’s a known effect of climate change,” said Greg Foltz, an oceanographer at NASA. “Increased ocean heat is causing strong hurricanes to become stronger.” The Atlantic Ocean between the Caribbean and Africa, the breeding ground for East Coast hurricanes, is the warmest it has ever been this time of year, with temperatures closer to what would be expected in August or September. Beryl is the earliest Category 5 storm (with sustained winds of 157 mph or greater) ever recorded in the Atlantic.
Can something be done about it?
The fundamental question is what measures are taken to limit climate change. But a better understanding of storm mechanics and better forecasting can lead to more timely warnings; Improvements to a network of floating ocean temperature sensors known as Argo, managed by an international consortium of scientific agencies, have proven critical to the latter. With Beryl, the National Hurricane Center was able to accurately forecast that the storm would strengthen into a hurricane (possibly even a Category 3 or higher) long before it hit the Windward Islands of the Caribbean.
