Insider Blog: Determining a hurricane’s storm surge and impacts

Currently, the state of Florida is preparing for a severe weather event, as Hurricane Idalia is rapidly strengthening and approaching parts of Florida's Gulf Coast. This specific area is where a Storm Surge Warning is in effect, with some areas seeing chances for Storm Surge inundation of 10-15 feet above ground level, and devastating waves.

Simply put, the storm surge is the abnormal rise of water over and above predicted tide levels. It's caused by strong winds in the hurricane or tropical storm, with low pressure making a small impact. Depending on several factors, this storm surge can be minimal, or it can be extremely destructive. Hurricane Idalia is forecasted to become a major storm by the time it reaches landfall, which is one of the factors of why storm surge is forecasted to be 10-15 feet. With it becoming a major storm closer to landfall, the shallow water stops winds from circulating through the water, and the winds then encourage the formation of waves.

There are several other factors that play into storm surge. Storm intensity plays a big part, as the stronger storms are associated with stronger winds. As I mentioned earlier, these stronger winds will help formation of storm surge. Forward speed of the storm will play another part, as a faster storm on the open coast will create a stronger storm surge as well. Storm size plays a part, mainly because the larger the storm, the more area it can impact. Angle of approach is a key, as a storm that approaches perpendicular to the coast is more likely to produce a stronger storm surge as well. Hurricane Idalia currently is tracking to approach with this trajectory, creating favorable conditions. Finally, features like the concave Gulf Coast that Idalia is approaching can encourage higher storm surges.