WASHINGTON: Hurricane Helene‘s torrential rain and powerful winds were made about 10 percent more intense due to climate change, according to a study published Wednesday by the World Weather Attribution (WWA) group.
Although a 10 percent increase “might seem relatively small… that small change in the hazard really leads to big change in impacts and damage,” said climate scientist Friederike Otto, who heads the research organization.
The study also found that fossil fuels — the primary cause of climate change — have made hurricanes like Helene 2.5 times more likely to occur.
In other words, storms of Helene’s magnitude were formerly anticipated once every 130 years, but now the probability is closer to once every 53 years, on average.
To conduct the study, researchers focused on three aspects of Hurricane Helene: precipitation, winds and the water temperature of the Gulf of Mexico — a key factor in its formation.
“All aspects of this event were amplified by climate change to different degrees,” Ben Clarke, a co-author of the study and researcher at Imperial College London, told a press conference.
“And we’ll see more of the same as the world continues to warm,” he continued.
The research by WWA, an international group of scientists and meteorologists who study the role of climate change in extreme weather events, comes as the southeastern US state of Florida prepares for the arrival of another major hurricane, Milton, just 10 days after it was hit by Helene.
Destruction
Helene made landfall in northwestern Florida on September 26 as a Category 4 hurricane with winds up to 140 mph (225 kph).
The storm then moved north, causing heavy rain and devastating floods in several states, including North Carolina, where it claimed the highest death toll.
The authors of the study emphasized that the risk posed by hurricanes has increased in scope beyond coastal areas.
Bernadette Woods Placky, chief meteorologist at NGO Climate Central, said Helene “had so much intensity” that it would take time for it to lose strength, but the “storm was moving fast… so it could go farther inland pretty quickly.”
This study utilized three methodologies to examine the three aspects of the storm, and was conducted by researchers from the US, the UK, Sweden and the Netherlands.
To study its rainfall, researchers used an approach based on both observation and climate models, depending on the two regions involved: one for coastal areas like Florida, and another for inland areas like the Appalachian mountains.
In both cases, the study found precipitation had increased by 10 percent because of global warming, which is currently at 1.3 degrees Celsius above pre-industrial levels.
To study Helene’s winds, scientists looked at hurricane data dating back as far as 1900.
They determined Helene’s winds were 11 percent stronger, or 13 mph (21 kph), as a result of climate change.
Lastly, the researchers examined the water temperature in the Gulf of Mexico, where Helene formed, finding it was around 2 degrees Celsius above normal.
This record temperature was made 200 to 500 times more likely due to climate change, the study asserts.
Warmer oceans release more water vapor, providing more energy for storms as they form.
“If humans continue to burn fossil fuels, the US will face even more destructive hurricanes,” Clarke warned in a statement.

Hurricane Helene has caused significant damage to Asheville’s famous attraction Biltmore Estate.
The 8,000-acre estate that hosts 1.4 million visitors a year suffered significant damage in some buildings after the hurricane ripped through Western California, as reported by CNN.
“We are still assessing impacts to the estate from Tropical Storm Helene and that will take some time,” the Biltmore said in a statement on Thursday.
The Biltmore Estate, known for housing America’s largest privately owned mansion, reported that the 250-room Biltmore House, winery, conservatory, and hotels “received minimal or no damage from the storm.”
However, low-lying areas on the estate, such as the entrance and farm, faced “significant flooding and damage to buildings.” The Biltmore said, “We sadly lost a few of our animals during the storm, but the vast majority are safe and accounted for.”
The forested portions of the Biltmore Estate, which represent a substantial part of the property, experienced extensive wind damage to the grounds and some structures. “Crews have been working tirelessly to clear roads so we can begin repairs,” the estate reported.
It’s not clear when the estate will reopen, but “Initial assessments indicate the estate will be closed to guests until at least October 15,” the Biltmore said on its website. “We will continue to provide updates about operations beyond that date as they are available.”
Biltmore Estate, located in Buncombe County, has become an unexpected epicentre of death and destruction from Hurricane Helene. As of Friday, at least 72 fatalities have been reported in the county, and approximately 78,000 homes and businesses are still without power, one week after the storm’s devastating impact.
The electricity substation serving Biltmore Village, a popular area just outside the estate, sustained catastrophic damage and will require months for repairs, according to Duke Energy.
“The water line is almost at the top of that substation,” said Duke Energy spokesperson Bill Norton.
“We can’t leave those customers without power for that long, so we’ve brought in a 200,000-pound mobile substation,” he added.
The mobile substation is expected to be operational by Sunday. “We’re digging new spots for wiring to ensure they are underground and safe,” Norton added.
In Western North Carolina, about 1,05,000 homes and businesses are facing “long-term” power outages due to Helene’s destruction of critical infrastructure.

Hurricane Helene wreaked havoc across Florida’s Big Bend region and beyond, causing widespread flooding and wind damage after making landfall Thursday night. The storm’s impact extended from the Gulf Coast of Florida to Georgia and the Appalachian Mountains, resulting in the loss of more than 40 lives across four states.
The Tampa Bay area experienced severe flooding, with entire neighbourhoods submerged due to a powerful storm surge.
In southern Georgia, rescue teams worked to extract residents, some injured, from damaged structures. Flood warnings were issued for over 2 million people in North Carolina, while millions more, including those as far north as Virginia, faced power outages.
The devastation spanned a distance of at least 800 miles from the storm’s landfall point in the sparsely populated Big Bend area of Florida, located where the panhandle meets the Florida Peninsula. Near Newport, Tennessee, a dam failure prompted a flash flood warning for 20,000 residents and forced the evacuation of a 7,000-person community. In the mountains of western North Carolina, landslides endangered homes and obstructed major roadways. Authorities issued an evacuation warning for residents downstream of the Lake Lure Dam, fearing its imminent failure.
Ryan Cole, assistant director for emergency services in Buncombe County, which includes Asheville, described the storm as “the most significant natural disaster that any of us have ever seen in western North Carolina.”
Among the storm’s fatalities were at least 17 people in South Carolina, 15 in Georgia, and seven in Florida. The hurricane made landfall just before midnight on Thursday as a Category 4 storm with winds of at least 130 mph. In Tampa, a falling sign claimed one life on a highway, according to governor Ron DeSantis, while several others drowned in other parts of the state.
The storm also spawned deadly tornadoes, with two people losing their lives in a tornado in Wheeler County, Georgia, as reported by local emergency management officials.
The vast extent of the area severely impacted by Helene is difficult to comprehend. In Atlanta, a television meteorologist covering the hurricane even rescued a woman live on the air as she cried out for help from inside her car, which was being engulfed by rising floodwaters.