What level of storm surge can the Charleston area expect from Debby?

CHARLESTON, S.C. (WCBD)- Tropical Storm Debby is expected to crawl across the southeast this week, dumping potentially historic amounts of rainfall along the South Carolina coast.

It made landfall in Florida’s Big Bend region Monday morning as a Category 1 storm but was downgraded to a tropical storm in the National Hurricane Center’s 11 a.m. advisory.

Still, forecasters have warned of life-threatening storm surges in Florida — in some places as high as six feet — and major flooding across southeastern states.

What is storm surge?

According to the National Hurricane Center, storm surge is defined as “an abnormal rise of water generated by a storm, over and above the predicted astronomical tides.”

Storm surge is a large dome of water often 50 to 100 miles wide that sweeps across the coastline near where a tropical system makes landfall. That dome is driven by wind and a change in atmospheric pressure, Storm Team 2 meteorologist Josh Marthers explained.

“It’s created by a lowering of atmospheric pressure so essentially the air is not as heavy on the surface of the ocean as normal so the surface of the ocean rises and that water moves onshore with the storm itself,” he said.

The surge of high water topped by the waves is devastating and the stronger the hurricane and the shallower the offshore water, the higher the surge will be.

What storm surge can the Charleston area expect?

Storm Team 2 predicts the Charleston metropolitan area could see water levels of about 2 to 4 feet above the ground in surge-prone areas, primarily along the coastline.

Storm Team 2 Meteorologist Grace Lowe said most of the tri-county area will see about 10 inches of rain through Friday morning, but some areas could see totals of up to 20 inches.

“We haven’t seen widespread rain totals of these amounts since the historical flooding event in October 2015,” Lowe said.

Timing will also play a factor. The water could reach a height of 2-4 feet above ground in the warning area if peak surge occurs at the time of high tide.

How can you protect your home against storm surge?

The combination of storm surges, battering waves, and high winds is dangerous and can cause property damage.

The greatest impacts, according to Storm Team 2, will be in flood-prone areas like downtown Charleston, along the islands, and in tidal waterways.

“If you take on water during what we call sunny day flooding, you’re going to take on water in this,” Josh said.

The Federal Emergency Management Agency (FEMA) notes that although homeowners cannot prevent storm surge, there are steps that can be taken to minimize damage and keep residents safe.

FEMA recommends homeowners take the following steps to protect their homes:

• Reinforce the garage door
• Protect windows and doors; seal cracks and gaps
• Secure objects outside the home
• Trim or remove dead, damaged, or rotting trees and limbs
• Store valuables and important documents on an upper floor

Sandbags can be used around doorways in flood-prone areas to prevent minor flood waters from entering homes.

Local municipalities are offering free sandbags to residents in preparation for Debby. You can find a full list of pick-up locations here.