Overfalls

Rough, disturbed water caused by tidal flow over uneven seabed or conflicting streams.

These areas often form where strong tidal streams pass over banks, ledges, headlands or sudden changes in depth. The surface may appear broken, steep, confused or choppy, even when conditions nearby look moderate. Sea state can become worse when wind opposes tide. Passage planning should take account of tidal timing, wind direction, vessel size and crew comfort. In small craft it may be better to avoid known areas during peak tidal flow.