Tidal bore

A tidal bore,[1] often simply given as bore in context, is a tidal phenomenon in which the leading edge of the incoming tide forms a wave (or waves) of water that travels up a river or narrow bay, reversing the direction of the river or bay's current.

The tidal bore induces a strong turbulent mixing in the estuarine zone, and the effects may be felt along considerable distances.

The low-frequency sound is a characteristic feature of the advancing roller in which the air bubbles entrapped in the large-scale eddies are acoustically active and play the dominant role in the rumble-sound generation.

In China, despite warning signs erected along the banks of the Qiantang River, a number of fatalities occur each year by people who take too much risk with the bore.

On the other hand, tidal bore-affected estuaries are rich feeding zones and breeding grounds of several forms of wildlife.

They include: Historically, there was a tidal bore on the Gulf of California in Mexico at the mouth of the Colorado River.

A bore in Morecambe Bay , in the United Kingdom
Video of the Arnside Bore , in the United Kingdom
The tidal bore in Upper Cook Inlet , in Alaska
Undular bore and whelps near the mouth of Araguari River in northeastern Brazil. The view is oblique towards the mouth from airplane at approximately 30 m (100 ft) altitude. [ 3 ]
The Trent Aegir seen from West Stockwith, Nottinghamshire , 20 September 2005
The Trent Aegir at Gainsborough, Lincolnshire , 20 September 2005
A tidal bore wave moves along the River Ribble between the entrances to the Rivers Douglas and Preston.
Tidal bore on the River Ribble
Tidal bore on the Petitcodiac River