Milton is the hurricane that scientists feared

When Hurricane Milton transformed from a Category 1 storm to a Category 5 storm in 12 hours yesterday, climate scientists and meteorologists were stunned. NBC6's John Morales, a veteran TV meteorologist in South Florida, choked up as he described how quickly and dramatically the storm had intensified. For most people, a 50 millibar pressure drop means nothing; A weatherman understands, as Morales said mid-show, “this is just terrible.” Florida is still cleaning up from Helene; This storm is moving much faster and is more compact and organized.

In some ways, Milton is exactly the kind of storm that scientists have warned about; Michael Wehner, a climate scientist at Lawrence Berkeley National Laboratory in California, called it shocking but not surprising. “One of the things we know is that in a warmer world, the most intense storms will be more severe,” he told me. Milton may definitely have been a significant hurricane, but every aspect of the storm that could have been produced was.

A hurricane is created by several variables, and in Milton the variables have combined to create a nightmare. The storm is gaining significant energy thanks to high sea surface temperatures in the Gulf of Mexico, which are far hotter than usual. And this energy leads to higher wind speeds. Milton also absorbs moisture from the very humid atmosphere, which can typically hold 7 percent more water vapor for every degree Celsius increase in temperature. Additionally, the air is very unstable and therefore can rise more easily, allowing the hurricane to form and maintain its shape. And thanks to La Niña, there isn't much wind shear — the wind's speed and direction are fairly consistent at different altitudes — “so the storm can stay nicely vertically stacked,” says Kim Wood, an atmospheric scientist at the University of Arizona. told me. “All of this together means that the storm uses the available energy more efficiently.” In other words, the storm became a major threat very efficiently.

This perfect combination of hot seas, moist air and low wind shear is aided by Milton's path through the western part of the Gulf of Mexico, which has not seen major storm activity this season. When a storm passes over hot water, it absorbs much of that heat and uses it as fuel, lowering the water temperature. But in the western Gulf, “there was nothing else to cool the water,” Wood told me.

Milton is also a very compact storm with a highly symmetrical, circular core, Wood said. In contrast, Helene's core took longer to coalesce and the storm remained more widespread. Wind speeds in Milton increased by about 90 miles per hour in a single day, strengthening faster than any other recorded storm except Hurricanes Wilma in 2005 and Felix in 2007. Climate scientists have feared for some time that climate change is causing such storms could intensify more quickly and reach higher peak intensities as they are further boosted by climate change. Milton does just that.

Rapid intensification has become more common in recent years. Hurricane Otis, which made landfall as a Category 5 near Acapulco, Mexico last year, strengthened into a tropical storm in a single day, confusing forecasters and leaving residents very little time to prepare for a direct hit to prepare for this size. Hurricane Idalia, also in 2023, was another example of rapid intensification, as was Hurricane Ian in 2022. Kerry Emanuel, a meteorologist and professor emeritus at MIT, predicted less than a decade ago that rapid intensification of hurricanes would be short before landfall would likely “become increasingly frequent and violent as the globe warms,” and in recent years that prediction has been confirmed in further modeling studies. It's a new addition to the canon of knowledge about climate change and is therefore not yet firmly established, but this early research suggests a link between rising temperatures and the rapid escalation of these storms. Climate change may actually reduce the total number of tropical storms and hurricanes (although the mechanism causing this decline is still debated), but the storms that actually form will likely be more intense, according to Tom Knutson, a senior scientist at the institute's laboratory in Geophysical Fluid Dynamics from the National Ocean and Atmospheric Administration. His most recent research found that more Category 4 and 5 storms may make landfall in the U.S. by the end of this century. Even if we get fewer storms, they will get worse.

Trying to weather storms of this magnitude can be deadly. Overnight, Milton was downgraded to Category 4 but grew in size. It could also worsen to a Category 5. Florida is now preparing to evacuate potentially more than 6 million people before Milton reaches the country. And the conditions it will collide with on land have already worsened due to climate change. According to an analysis by , sea levels in the Gulf of Mexico have risen twice as fast as the global average since 2010 The Washington Postand the sea along the Tampa Bay coast is now nearly five inches higher than it was 14 years ago. So if the storm surge inundates the coast, the salt water will likely advance farther inland and likely with greater force than it would otherwise.

Milton also looks like a “very wet” storm, Gabriel A. Vecchi, a professor of climate science at Princeton University, told me, and Florida is already soaking wet. The state has been inundated with rain, and the storm will be followed by more. The soil is already saturated and therefore cannot act as a sponge; Normally it would serve as a partial buffer against flooding.

Precipitation is one of the best-understood areas of “attribution science,” the discipline that models how much worse climate change is likely to have caused a given weather scenario. And climate change is clearly making hurricane rainfall worse. Wehner and two colleagues at Lawrence Berkeley National Laboratory published a preliminary analysis that found climate change may have caused up to 50 percent more rainfall in some locations in Georgia and the Carolinas during Hurricane Helene. “Instead of 10 inches, in some places they got 15.” Instead of 20 inches, they got 30,” Wehner told me.

Only after Milton's death will scientists try to explain how climate change made the storm more terrible than it otherwise might have been – perhaps still a severe storm, but not so violent and so fast that it would save a seasoned meteorologist from catching a cold would have. And the world is expected to continue to warm dramatically in the coming century; Storms like Milton are a preview of the species that will become more common, Vecchi told me. “We have a hard time dealing with such wet storms,” he said. “How do we deal with storms that are wetter?” Surely these, too, will be shocking. But they shouldn't come as a surprise: we knew they were coming all along.