With Irma or any hurricane, storm surge isn't just a coastal threat

This map shows the potential reach of storm surge impacts should a Category 2 hurricane make landfall in the Lowcountry. (NOAA)

Storm surge is often considered the most dangerous and destructive part of a hurricane. Leaders and forecasters watch hurricane tracks closely as communities hit by the storm surge are usually the ones most damaged by the storm.

"The worst storm surge, and the worst inundation occurs right around the center and just to the right of that track," said Blair Holloway, a lead meteorologist with the National Weather Service in Charleston.

This means if Irma were to make landfall in South Carolina, the worst damage would occur right at the eye and along the coast to the northeast of the eye. Sometimes this damage can occur dozens of miles away from the eye if the storm is big enough. “Don’t focus on the exact track of the center because the impact from the storm, including storm surge, can extend a good distance away from the actual center," said Holloway.

Storm surge is different from regular flooding in that its described as having part of the ocean move onto land for a period of time. “Imagine all this behind you, covered in water," said Dr. Lee Lindner, a professor of Atmospheric Physics from the College of Charleston as he referred to a salt marsh in West Ashley. "More importantly imagine five or eight foot waves on top of that. We’ve all seen pictures of Harvey and we’ve seen pictures of Katrina and New Orleans, all that water, that flooding. But they didn’t have the waves, and it’s the waves that can knock down homes.”

Another concern with storm surge is how it can travel up waterways and impact locations farther inland. “Surge will travel up rivers. A-matter-a-fact rivers tend to focus the surge a bit," said Lindner. "So even if we have... say… a 20 feet of surge at the mouth of the river, we could easily have 25 (feet of surge) up the river.”

The National Hurricane Center has a map that shows maximum estimated storm surge potential based on the size and strength of a storm. It should be noted that these are maximum potential estimates only, not set and stone. They're only accurate for areas directly near the eye or just to the right of the eye of a storm, and don't show potential storm surges for the entire length of a hurricane. A link can be found (HERE).