Storm surge is defined as "abnormal rise of water generated by a storm, over and above the predicted tides," according to NOAA. As it reaches increasingly shallow waters, this powerful vertical movement of water is pushed ashore, AccuWeather explains. This causes flooding, especially when the coast juts inland, like on the Gulf Coast, where Hermine made landfall.
Floods from storm surges are particularly powerful and can be deadly, such as during Hurricane Katrina and Superstorm Sandy.
Click here for the latest tropical weather news.
MORE HURRICANE & SEVERE WEATHER EXPLAINERS:
What is storm surge and why is it dangerous?
More TOP STORIES News