Hurricanes Milton and Helene Were Intensified by Climate Change, Researchers Find

Hurricanes — the most powerful storms on Earth — are becoming more widespread and destructive as a warming planet increases their intensity. Hurricanes Helene and Milton are following the trend of these storms becoming supercharged and more likely to form, according to a pair of studies from the World Weather Attribution (WWA). 

The researchers found that Hurricane Helene’s wind speed on the coast of Florida was about 11% stronger due to climate change, and its total rainfall increased by 10%. The high water temperatures that fueled Helene were found to be between 200 and 500 times more likely, and hurricanes the size of Helene are now 2.5 times more likely each year due to climate change, according to the report.

As for Hurricane Milton, the researchers found storms of its intensity are now 40% more common, hurricanes with heavy one-day events similar to Milton are 20-30% more intense and twice as likely, and the maximum wind speeds of similar storms are about 10% stronger due to climate change. 

This increase in wind speed, as the analysis points out, means that without human influence, Milton would have been a category 2 storm rather than category 3 when it made landfall, if it had formed at all.

“We conclude that warmer Sea Surface Temperatures along the track of Hurricane Milton were strongly influenced by climate change, which affected Milton’s environment and made it more likely for the storm to develop and intensify throughout its lifetime,” the researchers wrote.

The conditions that lead to the formation of hurricanes are complex, but there are a few general factors that influence their formation and behavior in the Atlantic Ocean. 

Hurricanes in the Atlantic typically form near the intertropical convergence zone — a low-pressure band roughly encompassing the equator, where the trade winds from the northern and southern hemispheres meet and are forced high into the atmosphere. This creates a stormy ring around the planet, which, combined with warm equatorial waters that evaporate into the atmosphere, creates ripe conditions for hurricanes, especially during hurricane season, from the beginning of June to the end of November.

Once a hurricane forms here, trade winds often push them Northwest, toward the Gulf of Mexico.

But these conditions are becoming even more conducive for hurricanes with climate change.

Bernadette Woods Placky, Chief Meteorologist at Climate Central, said the warming oceans and atmosphere are “like steroids for hurricanes,” according to a press release from the WWA.

“As Helene approached the U.S., it strengthened from a Category 2 to a Category 4 hurricane in just ten hours,” she said. “This rapid intensification is happening more often with climate change. If humans keep heating the climate, we will keep seeing storms rapidly morph into monster hurricanes, leading to more destruction.”

Hurricane Helene, which first hit Northern Florida as a category four storm and went on to devastate significant parts of Georgia, Western North Carolina and South Carolina, Eastern Tennessee and Southern Virginia, killed more than 200 people, the highest U.S. death toll from a hurricane since Katrina in 2005.

“There were many things that went right. For example, the major dams held, the hurricane was forecast and emergency evacuations were declared… and yet we still had a huge death toll,” Julie Arrighi, director of programmes at the Red Cross Red Crescent Climate Centre, told reporters in a briefing. 

She added, “I think that we start to see spots where there may have been things that need further unpacking in the days and weeks ahead — were there more evacuation options or not in some of the areas, for example — but I think it will be really interesting to see how this gets further analyzed through time.”

Along with Florida being at risk for hurricanes given its location in the Gulf of Mexico, the researchers in the flash study for Hurricane Milton attribute its low elevation and large coastal populations as major risk factors for these storms.

The study also noted that low-income areas and racial minority communities face the greatest risk from these storms, due to “inadequate housing and resources for adequate preparedness, evacuation, and recovery.” 

Also mentioned was the major stress placed upon infrastructure as millions tried to evacuate, leading to “severely congested” highways, while gas stations ran out of fuel, and the outflux of people led to crowded hotels and motels, many of which weren’t equipped to accommodate guests with “disabilities or health issues.” In addition, the researchers noted that while 37% of Americans cannot afford a $400 emergency, it can cost thousands for evacuees to seek refuge.

“We really need to be adapting and preparing for these unprecedented, very extreme events,” Arrighi said. “Even in a country that has a lot of preparedness — a lot of emergency readiness —  we still see these high impacts. Increasing the preparedness of these systems for these really large events is, I’m sure, a topic that will be talked about for many weeks and months to come.”