Experts say storm surges are one of the most dangerous conditions. (Learn more about hurricanes.)

“Before modern technology, storm surges caused the greatest number of fatalities,” says National Hurricane Center meteorologist Joel Cline. “Now it has the potential to cause the greatest number of fatalities.”

With advanced monitoring, Cline says people can be warned of oncoming surges before they hit, but once they're in harm's way, their odds of surviving drop.

Storm surges are simply onslaughts of ocean water that get pushed onto shore by strong winds. In the case of Florence, if the surge comes at high tide, Washington Post meteorologist Jason Samenow says surges could be 13 feet high, while Weather Underground meteorologist Jeff Masters says surges