In their study, Garner and his colleagues compared where storms form, how fast they are, and where they end. Comparing data from pre-industrial times to simulations stretching back to the end of the 21st century, the study found that tropical storms are 15% more likely to start than the southeast coast of the United States. According to the model’s simulations, storms are more likely to move 100 kilometers (62 miles) from both Boston and Norfolk than from New York City.
But Garner says the results don’t mean New Yorkers can breathe easy. While the analysis showed that the average storm could remain offshore, any individual storm would still pose a risk to the region. She says these future superstorms will move quickly while at sea, covering more land until they hit land and slow down. This means that they can make landfall faster. “One of the effects we’re seeing is that it takes less time to travel 100 kilometers from these cities,” she says.
Additionally, the team’s analysis found that there would be more storms along the East Coast, and because they would move slower, they would produce stronger winds and more water damage to homes and businesses. In fact, the longest-lived hurricanes will last twice as long as today’s storms. Garner continues, “Norfolk has seen the greatest impact in how long the storms last, but all three cities see effects that should prompt one to think about how to prepare for these events in the future.”
Hurricanes need warm water to survive, and most tend to become extinct once they cross the northern boundary of the Gulf Stream, a broad, fast-moving ocean current that brings warm tropical waters from the Gulf of Mexico past southern Florida, along Cape Hatteras and North Carolina, and then across the Atlantic into Europe. Two recent hurricanes, Dorian in 2019 and Matthew in 2016, were so strong that they slowed the current by 50 percent for several weeks, according to a paper published last year in Marine Systems Journal.
That study’s author, Tal Ezer, professor of Earth and ocean sciences at Old Dominion University in Norfolk, believes that if future hurricanes also change direction and speed, it could cause more havoc in the Gulf Stream. Ezer says the new study is a reasonable analysis of a possible future ocean system. “If these hurricanes can really change trajectories, that could have a huge impact on the Gulf Stream and ocean circulation,” he says. This is important because the Gulf Stream helps with mild temperatures in England and southern Europe, which would be cooler if slowed or stopped.
In the United States, coasts were hit by 19 tropical storms classified as multi-billion dollar disasters between 2010 and 2020, with a total of $480 billion in damage, adjusted for inflation. Slower storms are likely to push their price up, and that’s worrying some state and local officials. Norfolk and the surrounding Hampton Roads, Virginia area is home to the world’s largest naval base, and rising sea levels have caused daytime flooding in many neighborhoods over the past 15 years.