Red tide outbreak blossoms off Tampa Bay

Jeff Berardelli is WFLA’s Chief Meteorologist and Climate Specialist

Over the past week, a large outbreak of Red Tide has exploded in the Gulf just offshore from Tampa Bay. It can be seen on the NOAA Map below with red colors indicating high concentrations.

Red tide is a naturally occurring type of algae called Karenia brevis which is quite common, especially in the warmer months along Florida’s West Coast. It feeds off relatively warm waters and high levels of nutrients. If concentrations are high enough, it can cause the water to turn red.

The bloom is likely related to the passage of Hurricane Helene and Hurricane Milton. On Oct. 4, after Helene, FWC reported samples of red tide surrounding Pinellas County. To be clear, red tide blooms in the absence of hurricanes, but hurricanes are known to amplify outbreaks.

The theory goes that hurricanes upwell colder, more nutrient-rich water from the depths of the Gulf of Mexico and those nutrients then feed the growth and proliferation of the algae that cause these red tide outbreaks.

It seems reasonable to assume that runoff from nutrients on land like phosphorus and nitrogen can also enhance a bloom. During both Helene and Milton, storm surge and rainfall flooding would have flushed extra nutrients from land into Tampa Bay and the Gulf.

It seems no coincidence that blooms followed Hurricane Irma in 2018 , Hurricane Ian in 2022 , and now Hurricane’s Helene and Milton.

The red tide expanded fast. Pictured below are the NOAA satellite images of red tide from Oct. 11 through the 15.

Red tide can cause fish kills and respiratory distress to people nearby. It can last for weeks or even months.

For the latest news, weather, sports, and streaming video, head to WFLA.