Destructive hurricanes like Helene highlight that catastrophic impacts from storms can extend far inland
Destructive hurricanes like Helene are a stark reminder that significant and devastating impacts from many major storms are not relegated to coastal cities and communities -- inland regions often face catastrophic impacts too, experts are warning.
The Category 4 hurricane made landfall on Florida's Big Bend region Thursday night before tracking north, leaving a wake of destruction over 400 miles in the days the followed.
The storm brought 140 mph winds and a 15-foot storm surge to parts of the Gulf Coast, along with more than 20 reported tornadoes in five states. Helene, combined with a separate system, dumped over 30 inches of rain in parts of North Carolina over the span of a few days. At least 177 people died as a result of the storm, with many still unaccounted for.
Inland communities need to be prepared when tropical storms or heavy rain events hit, Jennifer Francis, an atmospheric scientist at the Woodwell Climate Research Center, told ABC News.
"We expect these sorts of events to happen more often," Francis said, adding that climate change is playing a major factor in these situations.
Because of the far-reaching impacts of tropical systems, meteorologists are now adding a growing number of regions to their forecasts, Marshall Shepherd, director of the Atmospheric Sciences Program at the University of Georgia and former president of the American Meteorological Society, told ABC News.
Human-amplified climate change is likely influencing the behavior of hurricanes in a variety of ways, research shows. Warmer sea temperatures are providing more fuel for tropical systems intensify more rapidly as they near the coast. More moisture in the atmosphere is triggerig more frequent extreme rainfall events. Some systems are stalling after hitting land, resulting in prolonged periods of intense rainfall over specific areas.
Several hurricanes that have struck in the last decade serve as a grim reminder that devastating impacts frequently extend far inland from where a storm first makes landfall along the coast, experts say.
Hurricane Ida and its remnants impacted a wide swath of the continental U.S. after making landfall in Louisiana in 2021 as a Category 4 storm. By the time the system got to the Northeast days later, it had transitioned into an extra tropical system that dumped over 3 inches of rain in one hour in New York City's Central Park, causing deadly flash flooding in some parts of the city.
"So much rain fell over a short period of time that you just got this massive flooding," Shepherd said. "That was what was overwhelming New York City."
In 2017, Hurricane Harvey slowed down after making landfall in eastern Texas as a Category 4 storm, bringing torrential rain and flooding to the Houston area for days even after it weakened to a tropical storm, Shepherd said.
Storm surge and rainfall are the deadliest impacts of hurricanes, which is why the Saffir-Simpson Hurricane Scale, which ranks the strength of tropical systems based on wind speeds, does not tell the whole story of the threats a hurricane presents, Shepherd said.
"There's a lot of work out there on alternative ways of representing the hazards from hurricanes," he said.
Multiple factors played into the catastrophic rainfall near Asheville, North Carolina, which had undergone a heavy rain event just before Helene, Shepherd said.
One of these factors is called orographic lifting. This occurs when air is forced to rise over a mountain and cool, causing water vapor to condense. This triggers cloud and precipitation that likely combined with Helene's tropical system to cause the torrential downpour, Shepherd said. The sheer size of the system extended the reach of the storm and researchers are looking into whether an atmospheric river also contributed to the heavy precipitation, Shepherd said.
"You sort of had this multiple-whammy of the hurricane, that orographic lifting from the mountains and this atmospheric river," he said. "Trillions of gallons of moisture coming in from the tropics."
In hilly and mountainous terrains, rainfall tends to be focused in valleys and rivers, which explains the flash flooding event in Asheville, Francis said.
"No terrain is going to do well when you dump 15 to 30 inches of rain on it over a short period of time, which is exactly what happened in Appalachia," Shepherd said.
The science behind the forecasting of Helene was near-perfect, especially with the amount of rain that the National Weather Service predicted days before, Shepherd said.
Communities may have been told about the impending storm but they aren't always prepared for the negative impacts, Kristina Dahl, a senior climate scientist at the Union of Concerned Scientists, told ABC News.
Early warning systems need to be very transparent, with wide-reaching communication systems, so that people know a threat is coming and have time to prepare and evacuate, Dahl said.
Local communities also need to prepare for all sorts of weather-related impacts by putting shelters in place and handing out hotel vouchers "so that things like personal finances don't present a barrier to getting yourself to safety," Dahl said.
Added Francis: "These inland communities, I think, are waking up to the fact that they are not immune to these tropical storms and these heavy precipitation events."
ABC News' Daniel Peck contributed to this report.
