Devastating Rainfall from Hurricane Helene
Hurricane Helene made landfall as a Category 4 storm on September 27, 2024, causing catastrophic rainfall and flooding across southern Appalachia and the Florida Gulf Coast. Record rainfall totals were observed, particularly in North Carolina, leading to severe disruptions and necessitating evacuations. NASA and FEMA are coordinating disaster response efforts in light of these devastating impacts.
In the fall of 2024, Hurricane Helene rapidly intensified as it approached Florida’s Big Bend area, ultimately making landfall as a Category 4 hurricane at 11:10 PM Eastern Time on September 27. Prior to landfall, the hurricane’s effects were already being felt on land due to a preceding rain event that began in southern Appalachia on September 25. The storm resulted in catastrophic flooding across several regions, including eastern Tennessee, western Virginia, and North Carolina. A map detailing rainfall accumulation for the three-day period ending at 7:59 PM Eastern Time on September 27, 2024, illustrates the storm’s impact. This data, derived from the Integrated Multi-Satellite Retrievals for GPM (IMERG), reflects remotely sensed estimates and may differ from on-the-ground measurements, as it represents averaged rainfall across specified areas. Notably, Asheville, North Carolina recorded an extraordinary 13.98 inches (35.52 centimeters) of rain from September 25 to 27, according to the National Weather Service. The extensive downpour caused severe flooding, inhibited road access, triggered landslides, disrupted electrical and cellular services, and necessitated evacuations to temporary shelters. In numerous rivers across the state, record flood crests were documented, demonstrating the widespread nature of the flooding that affected regions in Georgia, North Carolina, South Carolina, Tennessee, and Virginia, with some areas receiving rainfall totals nearing or exceeding 10 inches (25 centimeters). On the Florida coast, the heaviest precipitation was notably focused to the west of the hurricane’s center, particularly surrounding Apalachicola. Traditionally, for hurricanes in the Gulf of Mexico, heavy rainfall is observed to the east due to counterclockwise wind patterns drawing moisture from the ocean. However, in the case of Hurricane Helene, a frontal boundary over the Florida Panhandle contributed to unusual rainfall distribution, concentrating the most significant totals westward, as explained by Steve Lang, a research meteorologist at NASA’s Goddard Space Flight Center. Even areas of the Florida coastline that did not experience intense rainfall were affected by flooding due to storm surge, with several Gulf Coast towns, including Cedar Key and Tampa, facing adverse conditions. In response to the devastating outcomes of the storm, NASA’s Disasters Response Coordination System has been activated to support various agencies, including FEMA and the Florida Division of Emergency Management. The team has indicated that maps and data products will be made available via their open-access mapping portal to provide updates on flooding, power outages, precipitation totals, and additional relevant information. NASA Earth Observatory created an image illustrating the storm’s impact, utilizing IMERG data from the Global Precipitation Mission at NASA/GSFC, with the narrative contributions made by Lindsey Doermann.
Hurricane Helene serves as a pertinent case study in understanding the devastating impacts of tropical storms on land, particularly regarding rainfall and flooding. The historical context of hurricanes and their systematic monitoring through satellite data, such as that provided by the GPM mission, allow for accurate assessments of rainfall and consequent flooding risks. Analyzing such disasters underscores the significance of advanced meteorological research and coordinated disaster response efforts to mitigate the effects on affected regions. This highlights NASA’s role in utilizing scientific data to inform and assist in emergency management following significant natural disasters.
The occurrence of Hurricane Helene in fall 2024 exemplifies the catastrophic potential of tropical storms, which can lead to extensive rainfall and flooding, particularly in the southern Appalachian region. The unprecedented rainfall recorded in areas such as Asheville, North Carolina, and the subsequent severe impacts observed across several states emphasize the necessity for effective disaster response coordination. Initiatives by organizations such as NASA, FEMA, and state emergency management agencies are vital in responding to such disasters and mitigating their effects on communities.
Original Source: earthobservatory.nasa.gov
