What Do Beach Warning Flags Mean?

According to the Centers for Disease Control and Prevention (CDC), it is estimated that most unintentional drownings take place in what the CDC calls natural waters. These are the fresh and saltwater beaches across the U.S. Many more drownings are prevented with beach warning flags. Beach warning flags are visible informational signals that report the condition of the beach and the water. Oftentimes this is the only way to warn those on the beach of hazards.

Beach warning flags come in the colors red, yellow, orange, green, black, blue and purple. Some are blank while others have symbols. According to the Florida Coastal Management Program, beach warning flags are a standard size of 29.25 inches in height and 39 inches wide.

The red, yellow, orange and green flags are warnings about the currents or surf. One or two red flags or a black flag means "high surf and no swimming," while green means "calm waters." Yellow signs report light surf or currents and advise caution. Orange flags may be triangular, in which case they indicate dangerous environmental air or water quality.

Purple or blue flags may occasionally be seen on ocean beaches. These denote “dangerous marine life” in the water, according to the Florida Department of Health. This includes sharks, jellyfish and other dangerous animals in the water. The use of the purple or blue depends on the geographic locale (Florida uses purple).

Red signs often carry a symbol of a swimmer in across with a line across it meaning "no swimming." There is no swimming on red, black, blue or purple flags.