Flash Flood in York County, South Carolina

A stream gauge on the Catawba River indicated flash flooding developed after 5-9 inches of rain fell over the basin over two days. One to two inches of that fell in less than six hours during the morning of the 27th. The main impacts were just downstream of the Highway 21 bridge, where Herrons Ferry Rd and Brakefield Rd and adjacent parks/greenways and parking lots were inundated. Additionally, Wildcat Creek briefly overtopped its banks and inundated McConnells Highway.

Tropical Cyclone Helene began organizing over the western Caribbean on the 23rd and 24th of September before rapidly intensifying as it moved north through the eastern Gulf of Mexico on the 25th and 26th. A plume of moisture extending from the intensifying storm interacted with a slow-moving cold front to produce a band of widespread heavy rain showers and embedded scattered thunderstorms over the southern Appalachians and vicinity on the 25th and 26th, resulting in a predecessor heavy rainfall event over the mountains and portions of the foothills. Helene made landfall in the Florida Big Bend and moved quickly N/NE through Georgia before turning toward the N/NW once the remnant center reached northeast Georgia. Tropical rainbands around the center of Helene swept over areas with already-saturated soils over the mountains and foothills during the early morning of the 27th, resulting in very heavy rainfall and significant flash flooding across multiple basins with headwaters near the Blue Ridge escarpment. Due to its quick movement, Helene was still a strong tropical storm when the wind field reached the western Carolinas and northeast Georgia. Frequent wind gusts of 55 to 70 mph, with occasional gusts of 80 mph...and likely as high as 90 mph across the higher elevations combined with saturated soils to produce widespread damage to trees and electrical infrastructure. Hundreds of trees fell on houses, vehicles, and power lines throughout the area, resulting in several fatalities. Almost all customers in several counties lost power for at least a brief period. Most people were without power for at least a couple of days, while thousands were without power for a week or more.