Tidal bore
（重定向自Bore tide）
![](/Images/godic/202501/01/-Arnside_bore_small.ogg1554.jpg")
![A bore in Morecambe Bay, the United Kingdom.](/Images/godic/202501/01/Tidal_Bore_-_geograph.org.uk_-_3245811554.jpg")
![The tidal bore in Upper Cook Inlet, Alaska](/Images/godic/202501/01/Turnagain-bore1554.jpg")
![Undular bore and whelps near the mouth of Araguari River in north-eastern Brazil. View is oblique toward mouth from airplane at approximately 100 ft (30 m) altitude.[3]](/Images/godic/202501/01/Undular_bore_Araguari_River-Brazil-USGS-bws000261554.jpg")
A tidal bore, 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 against the direction of the river or bay's current.