EF1 tornado in Charleston County, South Carolina

A National Weather Service storm survey team confirmed that an EF-1 tornado with estimated peak winds of 90 mph and associated with Helene, impacted portions of Wadmalaw Island. The tornado, possibly beginning as a waterspout just west or northwest of Rockville, downed several large trees along Brigger Hill Road and McCants Road. The tornado then quickly travelled north snapping and blowing down several cluster of large hardwood trees along Leadenwah Drive and Allendale Plantation Road before dissipating in an area of water and marsh south of Heron Island Way. The tornado was likely at its strongest passing over Leadenwah Drive where the tree damage was the most extensive.

Helene first developed into a tropical storm in the northwest Caribbean Sea in the late morning of September 24, and strengthened into a hurricane near the Yucatan peninsula about 24 hours later. Helene continued to strengthen and became a major hurricane as it moved to the north-northeast across the eastern Gulf of Mexico. Helene made landfall in the Big Bend region of Florida in the late evening hours of September 26 as a category 4 hurricane. Once inland, Helene moved quickly northward through the state of Georgia and produced widespread significant impacts across multiple states.

The very large wind field associated with Helen produced widespread tropical storm force winds across southeast South Carolina during the evening and overnight hours of September 26-27. The peak observed wind gust in southeast South Carolina was 75 mph at the Beaufort Marine Corps Air Station (KNBC). Wind impacts due to Helene were significant including widespread tree damage and power outages with several counties reporting near 100 percent power outages. Conditions along the east side of the track of Helene were very conducive to tropical tornadoes, and 8 tornadoes were confirmed across southeast South Carolina. Fortunately, there were no injuries or fatalities due to the tornadoes or strong winds associated with Helene.

Helene also produced heavy rainfall across southeast South Carolina. Rainfall amounts ranged from 2-5 inches in most areas, with the heaviest swath of rain occurring across Jasper, Hampton, Allendale, and Colleton counties where amounts were more on the order of 5-8 inches. However, no significant flooding or flash flooding was observed due to heavy rainfall.

Helene did produce modest storm surge along the southeast South Carolina coast, resulting in a peak observed tide level of 2.26 ft MHHW (8.02 ft MLLW) at the Charleston Harbor National Ocean Service (NOS) tide gage.