What is a tidal bore?

A tidal bore is characterized by a high wave generated by the tide crest moving into a river or estuary. This phenomenon occurs when the tide rises rapidly and pushes water upstream against the current of the river, creating a noticeable wave that can travel several kilometers inland. The energy of the incoming tide can cause a steep wave front that is often navigable by small boats and can be an impressive sight, particularly in regions where river estuaries funnel tidal waters.

The other options do not accurately describe a tidal bore. A low tide exposing riverbanks pertains to different tidal dynamics, while a decrease in tidal fluctuations over time and a gradual rise in sea level relate to broader oceanographic changes rather than the immediate and dynamic process of a tidal bore. Understanding the mechanics and characteristics of tidal bores is essential in the study of tidal phenomena and their impact on aquatic ecosystems and navigation.