JACKSONVILLE BEACH, Fla. – Officials have a warning for beachgoers this Memorial Day weekend after numerous men-of-war wash ashore at area beaches.

Jacksonville Beach lifeguards told News4Jax they will be flying purple flags this weekend to warn visitors about dangerous marine life. Men-of-war have been spotted in Jacksonville Beach, Mickler's Beach and in Nassau County.

Jacksonville Beach Ocean Rescue Capt. Rob Emahiser said Friday that lifeguards expect to see more men-of-war throughout the weekend.

"We do if the wind continues out of the east and the southeast because most of the jellies and men-of-war are driven by wind and the current," Emahiser said.

People planning on visiting the beaches are asked to be on the lookout for the bright-colored marine animals in the water and on the shoreline, as their tentacles can deliver a painful sting.

Surf Zone Forecast for Northeast Florida and Southeast Georgia: Water temperature: Near 80 |

UV index: 11 - Extreme | Lightning threat: None | Rip current risk: Low risk

A man-of-war is not jellyfish, but an animal made up of a colony of organisms known as a siphonophore. It is most prevalent on the Florida East Coast from November to March. They consist of a blue-colored, bladder-like balloon with tentacles, which reach out below the surface of the water and are up to 40 feet long.

Coming into contact with the tentacles can cause a painful sting lasting up two hours. Some man-of-war stings have even been deadly in some cases.

If stung, peel or wipe the tentacles off as quickly as possible. Apply vinegar or warm water to the affected area. Seek further aid from lifeguards or call 911 if you are susceptible to allergic reactions from insect stings.

Lifeguards told News4Jax that despite popular belief, urinating on a man-of-war sting will not help.