Understanding Weather Warning Flags

Rectangular Red Flags

A red flag means that high surf or strong currents, such as rip currents, are present.

Notice double red flags? If so, you'll have little choice but to avoid the beach altogether, since this means the water is closed to the public.

Red Pennants

A single red triangle (pennant) symbolizes a small craft advisory. It is flown whenever winds of up to 38 mph (33 knots) are expected to be a danger to your sailboat, yacht, or other small vessels. 

Small craft advisories are also issued when sea or lake ice exists that could be hazardous for small boats.

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How to Read the Symbols and Colors on Weather Maps

By Tiffany Means

Double Red Pennants

Whenever a double pennant flag is hoisted, be warned that gale-force wind (winds of 39-54 mph (34-47 knots)) are forecast.

Gale warnings often precede or accompany a hurricane watch but can be issued even when there's no threat of a tropical cyclone.

Rectangular Red and Black Flags

A single red flag with a black square center signifies a tropical storm warning. Whenever this flag is raised, be on the lookout for sustained winds of 55-73 mph (48-63 knots). 

Double Rectangular Red and Black Flags

University of Miami sports fans will no doubt recognize this next flag. Double red-and-black-square flags indicate hurricane-force winds of 74 mph (63 knots) or higher are expected to impact your forecast area. You should take precautionary measures to protect your coastal property and your life!

Beach Warning Flags

In addition to flying weather flags, beaches follow a similar practice that makes visitors aware of water conditions and advises guests whether or not to enter the ocean based on those conditions. The color code for beach flags includes: 

• Green flags are an "all-clear" and symbolize that the risk of hazards is low and it's safe to swim. 
• Yellow flags indicate moderate surf. You'll typically see these when ocean conditions are rough, but not life-threatening. 
• Purple flags are flown when dangerous marine life (jellyfish, sharks, etc.) have been spotted. They indicate you should exercise caution while in the water.
• Red flags are the most serious of all beach flags. They signal a serious hazard.

Unlike weather flags, the shape of beach flags doesn't matter — just the color. They may be triangular in shape or in the classic rectangular shape.