Hurricane Helene became a Category 4 storm upon making landfall in Florida’s Big Bend on September 27, 2024. It initiated heavy rainfall and flooding across southern Appalachia beginning September 25, causing significant damage and leading to evacuations. In Asheville, NC, 13.98 inches of rain were recorded, while areas in Florida also faced flooding despite lower rainfall amounts. NASA’s response teams are supporting recovery efforts and sharing vital information regarding the storm’s impact.
Hurricane Helene experienced intensification as it neared Florida’s Big Bend region in the fall of 2024, ultimately making landfall as a Category 4 hurricane at 11:10 p.m. Eastern Time on September 27. Prior to making landfall, the hurricane began producing catastrophic effects on land—including significant rainfall—well in advance of its eye reaching the coast. Starting on September 25, a preceding rain event and the primary storm brought heavy precipitation to the southern Appalachians, causing severe flooding across eastern Tennessee, western Virginia, and North Carolina among other regions. Data provided by IMERG (the Integrated Multi-Satellite Retrievals for GPM) revealed rainfall accumulation over the three-day period culminating at 7:59 p.m. Eastern Time on September 27, 2024. It should be noted that these remotely sensed estimates may diverge from ground-based measurements. For example, IMERG data represents averaged values within a given pixel, which may result in significant variations when compared to local rain-gauge measurements. According to records from the National Weather Service, Asheville, North Carolina, experienced a remarkable total of 13.98 inches (35.52 centimeters) of rainfall between September 25 and September 27. The storm wreaked havoc by inundating neighborhoods, compromising roadways, causing landslides, disrupting electrical and cellular services, and obliging numerous residents to seek refuge in temporary shelters. Many rivers in the state recorded unprecedented flood crests, with preliminary rainfall totals nearing or exceeding 10 inches (25 centimeters) observed across parts of Georgia, North Carolina, South Carolina, Tennessee, and Virginia. Contrary to usual patterns where heavy rainfall is typically observed to the east of a storm’s center in Gulf hurricanes, the heaviest precipitation from Helene was concentrated west of the storm’s center, particularly in the vicinity of Apalachicola, Florida. This unusual distribution was attributed to a frontal boundary over the Florida Panhandle that interacted with the hurricane’s circulation, thereby funneling moisture and generating extraordinary rainfall totals. Steve Lang, a research meteorologist at NASA’s Goddard Space Flight Center, elucidates this anomaly. Despite some areas along the Florida coast receiving less precipitation, they were not immune to flooding phenomena. Towns and cities along the Gulf Coast, including Cedar Key and Tampa, also experienced flooding as a result of storm surge associated with the hurricane. The NASA Disasters Response Coordination System has been activated to provide support for various agencies engaged in recovery efforts from the storm, including FEMA and the Florida Division of Emergency Management. The team is collaborating to post maps and pertinent data on an open-access mapping portal as more information about flooding, power outages, and precipitation totals becomes available.
In the late summer and early fall months, hurricanes often form in the Gulf of Mexico, driven by warm ocean waters and atmospheric conditions conducive to storm formation. These phenomena can lead to tropical storms and hurricanes that may impact coastal and inland regions significantly. Rainfall associated with hurricanes can lead to severe flooding, landslides, and infrastructure damage, particularly in areas that might already be saturated from previous rainfall events. Predicting the track and intensity of hurricanes remains a critical component of disaster preparedness, as advance knowledge can aid in evacuation efforts and the allocation of resources for emergency response.
In summary, Hurricane Helene showcased the catastrophic impacts that hurricanes can inflict, even before making landfall. With record rainfall totals leading to severe flooding across several states, the critical need for emergency response and support is evident. The unique precipitation patterns observed with this storm underline the complexities of hurricane behavior, emphasizing the importance of thorough meteorological analysis in disaster preparedness and response efforts.
Original Source: earthobservatory.nasa.gov
