“This could be the deadliest hurricane in Florida history.”
This is how US President Joe Biden described the consequences of powerful Hurricane Ian, which furiously hit the west coast of Florida this Wednesday as a category 4 cyclone with winds of more than 240 km/h, causing flooding. catastrophic in several locations.
The hurricane, which over time was downgraded to a tropical storm, caused a storm surge several meters high which flooded large areas of Florida’s southwestern coast and left more than 2.6 million homes without power.
“It is one of the five worst hurricanes that have hit the Florida peninsula”Florida Governor Ron DeSantis said Wednesday.
But Hurricane Ian not only caused great damage, but also caused a curious phenomenon on the coast of West Florida known as reverse storm surge.
This caused the ocean water to disappear from Tampa Bay and other areas on Wednesday morning, just before the cyclone made landfall.
The images on social networks showed the wet sand of the bay that was left once the water “disappeared”. Several passers-by ventured to approach and walk on the algae that were left out in the open.
The US National Weather Service. shared an image of what happened, issuing a warning. “Important note: the water will return. Don’t try to walk there or anywhere else the water has receded.”
Later the water would not only return, but it would do so with “catastrophic” tides, as the National Hurricane Center (NHC).
The last time a registered reverse storm surge in Tampa was in 2017during the passage of Hurricane Irma, which also reached the US with category 4.
To understand why this happens, we must pay attention to several factors, such as the structure of the hurricane and its winds.
The winds of tropical cyclones, when they form north of the Equator, circulate counterclockwise, that is, from right to left.
The western coast of Florida is located in the opposite direction of the rotation of the cyclone. Therefore, in the areas to the north of the hurricane, it causes the water to recede into the ocean due to the force of the winds.
In contrast, in areas to the south, the cyclone’s winds cause ocean water to enter as a storm surge.
According to meteorologist José Álamo, of the US National Weather Service, when the storm surge occurs in reverse there is usually a “low tide” before the arrival of the cyclone.
“When the water recedes, it means that the hurricane is on its way,” he said.
the return of the sea
However, the movement of the hurricane’s winds leads to a change of direction when moving through an area: what was going in one direction, when the cyclone changes position, returns in the opposite direction.
So, when the area that was to the north of the hurricane becomes to the south, the same thing happens, but in the opposite direction. It is what we call upwelling or coastal flooding of a hurricane.
It also happens that when the hurricane moves away from the place where the waters have receded, they can slowly return, as the tropical system leaves the area. (YO)