What the flags mean

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Red - Very Strong Fluvial Flows

• Conditions are difficult and dangerous.

• All man-powered vessels are advised not to go afloat on the ebb tide.

Yellow - Strong Fluvial Flows

PLA advise man-powered vessels:

• Beginners, novices, younger junior (J15's and younger), or any weaker crews, and those that do not usually navigate on the tidal section of the River Thames not to go afloat on the ebb tide.

• All river users of man-powered vessels should navigate with extreme caution and consider whether it is safe for them to go afloat on the ebb tide.

Green - Average Fluvial Flows

• All river users to navigate with caution and maintain a proper look out.

Black - Low Fluvial Flows

• Fluvial flow is lower than usual. River users should expect lower than predicted tides, especially around low water.