EF1 tornado in Charleston County, South Carolina

A National Weather Service Storm Survey Team confirmed an EF1 tornado with an estimated maximum wind speed of 87 mph in Isle of Palms, South Carolina occurring from 1233 AM to 1237 AM EST.

The brief tornado, associated with an outer rainband from Tropical Storm Debby, moved onshore near 25th Avenue where it did minor roof damage to one house and also pulled the front door out the frame. The tornado continued north-northwest along 25th Avenue between Palm Boulevard and Hartnett Boulevard, where it pulled out a few windows and snapped/uprooted some trees. As the tornado moved just north of Hartnett Boulevard, it removed the shingles from a portion of the roofs from a few homes. Beyond this point, the tornado curved a bit more northwest and snapped a few more trees before starting to lift near the intersection of Waterway Boulevard and 24th Avenue, then dissipated within the Intra Coastal Waterway. Overall, an estimated 29 homes sustained some level of damage, either directly by the tornado or from trees or large limbs falling on them.

Debby first developed into a tropical storm about 100 miles west-southwest of Key West, Florida late afternoon on August 3rd, then gradually strengthened to a strong tropical storm while tracking north across the eastern Gulf of Mexico on August 4th. Debby then reached hurricane force strength late on August 4th about 100 miles west-northwest of Tampa, before continuing a north-northeast track across the eastern Gulf of Mexico and eventually making landfall near the Big Bend area of Florida as a Category 1 Hurricane during the morning of August 5th. Debby continued inland and weakened to a tropical storm while tracking northeast across northern Florida later on August 5th, then continued a gradual weakening trend while tracking across Southeast Georgia as a tropical storm (45 mph) before slowly emerging off the Southeast Coast at tropical storm strength (40 mph) near Tybee Island, Georgia on August 6th. Debby then tracked east and farther offshore early August 7th, then turned north and became a strong tropical storm (60 mph) over the Gulf Stream later that morning, before taking a more north-northwest track back toward the Southeast Coast and making landfall near Awendaw/Bulls Bay, South Carolina as a tropical storm (50 mph) around 2 AM on August 8th. A minimum surface pressure of 994 mb was recorded at Sullivan's Island (XSLV), South Carolina prior to Debby making landfall. After landfall, Debby continued on a north-northwest track across South Carolina as a tropical storm into mid day August 8th, before weakening to a depression later that day and continuing a north path across North Carolina and Virginia into early August 9th.

Across Southeast South Carolina, the main impacts associated with Debby included flash flooding due to widespread heavy rainfall, several nighttime tornadoes within rainbands and scattered tree damage associated with near tropical storm force winds.

Prolonged heavy rainfall across Southeast South Carolina brought widespread flash flooding on August 5th and 6th, additional areas of flash flooding on August 7th, 8th and 9th, along with considerable and prolonged flooding of creeks, streams and main stem rivers for several days thereafter. Numerous homes and roads were flooded, leading to rescues and/or evacuations. Storm total rainfall amounts from August 4th to August 9th generally ranged between 4 to 22 inches with highest amounts across the Quad County Area (Berkeley, Dorchester, Charleston, Colleton) and particularly along a stretch from Summerville, Ridgeville, St George and Harleyville, South Carolina to Moncks Corner, South Carolina. A peak storm total rainfall of 22.02 inches was recorded by a CoCoRaHS observer approximately 6.6 miles southwest of Moncks Corner, South Carolina. A daily record rainfall of 4.71 inches was also set on August 6th at the Charleston International Airport (KCHS). Despite a large amount of rain and flash flooding, storm surge/coastal flooding did not lead to mentionable impacts locally. The highest water level at the Charleston (CHTS1) tide gauge was 1.06 ft MHHW during the evening of August 5th. No injuries or fatalities occurred with flash flooding/flooding.

Several rainbands associated with Debby brought 8 tornadoes (4 EF1 and 4 EF0) across coastal counties of Southeast South Carolina during the night of August 5th into early August 6th, causing damage to numerous trees and many structures. An EF1 tornado in Berkeley County caused 2 minor injuries when a car was flipped by the tornado. A total of 2 minor injuries and no fatalities occurred with tornadoes.

Tropical storm force winds/gusts produced scattered tree damage and communication/power outages across several counties. One minor injury occurred when a tree fell down on a vehicle in Beaufort County, South Carolina. Strongest winds were recorded across coastal areas and nearby coastal waters. The highest sustained tropical storm wind (39 knots) and highest tropical storm wind gust (55 knots) occurred at Folly Beach South End (XFSE), South Carolina. Across nearby coastal waters, the highest sustained tropical storm wind (44 knots) and highest tropical storm wind gust (51 knots) occurred at the Edisto Buoy (41004). A total of 1 minor injury and no fatalities occurred by tropical cyclone winds.