Most of SC is under a flash flood watch. Do you know what that means?

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As Hurricane Florence continues to move inland through South Carolina, most of the state has been placed under a flash flood watch by the National Weather Service.

There are specific areas in S.C. that have been issued flood warnings, but there is a difference between that and flash flooding.

“Flooding is an overflowing of water onto land that is normally dry,” according to the National Severe Storms Laboratory. A flash flood is “the most dangerous kind of floods, because they combine the destructive power of a flood with incredible speed and unpredictability.”

What makes flash flooding potentially lethal is how fast it can occur.

“Flash floods occur within a few minutes or hours,” the National Weather Service stated, adding “most flood deaths are due to flash floods.”

Another thing that distinguishes a flash flood is the timeline.

Flash floods “begin within 6 hours, and often within 3 hours,” per weather.gov. A flood will occur 6 hours after an event has ended, according to the SulCom Summer Weather Program.

The event can include “heavy rainfall, a dam or levee break, and/or a mudslide,” weather.gov reported.

In this case, the event is Hurricane Florence and the massive amount of rain it is forecast to dump.

The National Weather Service called flash flooding the No. 1 weather-related killer in the U.S. for two reasons — “rainfall intensity and duration.”

Both are factors with the current storm that has hit the Carolinas.

“Hurricane Florence is expected to slowly move westward toward the region through Saturday, with the storm moving through the area over the weekend,” according to the National Weather Service Office in Columbia. “The slow movement combined with prolonged periods of torrential rainfall may cause flash flooding of creeks, streams, roadways, and washouts of area bridges may occur.”

Flash flooding is not limited to cities and towns near a body of water that could overflow.

Flash floods are as much of a risk in urban, or highly populated areas, because “buildings, highways, driveways, and parking lots increases runoff by reducing the amount of rain absorbed by the ground,” according to the NSSL.

So with so much of S.C. under a flash flood watch, that means the NWS is telling people in those areas that “conditions are favorable for a flash flood. It does not guarantee the area … will endure a flash flood, but provides a heads up,” the Atlanta Journal Constitution reported.

But take caution. Because as weather.gov points out, “flash flooding is possible everywhere.”

Flash Flood Watch

▪ Lancaster County

▪ Chesterfield County

▪ Newberry County

▪ Fairfield County

▪ Kershaw County

▪ Saluda County

▪ Lexington County

▪ Richland County

▪ Lee County

▪ Sumter County

▪ Orangeburg County

▪ Clarendon County

▪ Calhoun County

▪ Horry County

▪ Georgetown County

▪ Charleston County

▪ Berkeley County

▪ Williamsburg County

▪ Dorchester County

▪ Dillon County

▪ Marlboro County

▪ Union County

▪ Laurens County

▪ Greenwood County

▪ Greenville County

▪ Pickens County

▪ Oconee County

Source: National Weather Service Columbia