Tidal Bore Formation
Bay of Fundy dynamics · bore propagation · estuary funneling
Physics: A tidal bore forms when a large tidal wave (macrotidal range >4 m) enters a funnel-shaped estuary. The incoming tidal crest steepens as the cross-section narrows and depth decreases. When wave speed c = √(gd) cannot keep up with tidal forcing, a hydraulic jump (bore) forms, propagating upstream as an undular or turbulent wave. Froude number Fr = V/√(gd). Bay of Fundy: 16 m range, world record. Amazon (Pororoca), Qiantang (China), Severn (UK) also notable.