Bay of Fundy at Saint John and the drama of extreme tides

At Saint John on Canada’s Bay of Fundy, cliffs, river and harbour share one of Earth’s most dramatic tidal ranges, revealing a shifting coastline over each day.

At Saint John on Canada’s Bay of Fundy, the sea rises and falls by several metres against the harbour walls in a tidal rhythm that defines the whole shoreline. The bay lies between New Brunswick and Nova Scotia on Canada’s Atlantic coast and is widely recognised for its exceptional tidal range, which reaches about 16 m (52 ft) in some inner basins.

Tidal range that reshapes the coastline each day

Bay of Fundy is known for having one of the highest tidal ranges recorded anywhere, with differences between low and high tide that reach around 16 m (52 ft) in parts of the system.one of the highest tidal ranges The tides follow a semi-diurnal pattern, with two high tides and two low tides each day separated by a little over six hours, so the water level at Saint John’s waterfront is in constant motion.semi-diurnal pattern

Across the whole bay, the height of the tide difference increases from a few metres near the mouth to well over 10 m in narrowing inlets such as Minas Basin, and in one half-day tidal cycle around 100 billion tonnes of seawater flow in and out of the basin.height of the tide differencebillions of tonnes of seawater At Saint John this movement is visible in the changing water level against quay walls and rock ledges and in the alternating exposure and flooding of low-lying shore platforms and mudflats.

Saint John, the river mouth and the Reversing Falls

Saint John stands on the New Brunswick side of Bay of Fundy, at the point where the Saint John River meets Fundy waters in a narrow gorge cut through resistant rock ridges.where the Saint John River meets Fundy waters Here the strong rising tide from the bay interacts with the river flow to produce the Reversing Falls, a sequence of rapids, whirlpools and standing waves that changes character with the stage of the tide.Reversing Rapids near the river mouth

At low tide the river’s current dominates and water surges seaward through the gorge, while around high tide the rising Bay of Fundy waters push back against the river, reversing the flow and forming powerful rapids and waves at the surface.changing flow between river and bay Between these phases comes a brief period of slack tide, when river and bay meet with roughly equal force and the water surface in the gorge becomes relatively flat.

Fundy geology, cliffs and mudflats along the New Brunswick coast

Bay of Fundy occupies an ancient rift basin formed in the late Triassic period during the breakup of the supercontinent Pangaea, when the crust of eastern North America stretched and subsided between fault lines and later filled with seawater.ancient rift basin formed The result is a long, funnel-shaped bay whose geometry resonates with the Atlantic Ocean’s tidal rhythm and magnifies the incoming tide as it travels landward.

Along the New Brunswick shore, steep bedrock cliffs rise above coves and channels, and intertidal flats, salt marshes and shore platforms extend from their base.steep bedrock cliffs and coves Around Saint John, parks and protected areas along the Fundy coast present a mix of forest, exposed rock and broad stretches of mudflat shaped by erosion and the repeated advance and retreat of the sea.parks and protected areas along the Fundy coast

Visiting Bay of Fundy: what travellers from Western Europe should know

• Bay of Fundy stretches between the Canadian provinces of New Brunswick and Nova Scotia, with Saint John on its New Brunswick shore and Saint John River entering the bay beside the city.
• The shoreline around Saint John includes harbour walls, rocky ledges, steep coastal slopes and sections of tidal mudflat and shore platform that are periodically exposed and covered by the tide.
• Saint John lies in Canada, where the official languages are English and French and the national currency is the Canadian dollar.
• Entry requirements depend on your nationality; UK travellers can check the FCDO travel advice at gov.uk/foreign-travel-advice, Irish travellers the Department of Foreign Affairs at ireland.ie.

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Frequently asked questions about Bay of Fundy

Where is Bay of Fundy in relation to Saint John?

Bay of Fundy lies between the Canadian provinces of New Brunswick and Nova Scotia, with Saint John positioned on its New Brunswick shore where the Saint John River meets the bay.

What should visitors expect from the tides at Saint John?

Visitors encounter a semi-diurnal tidal pattern, with two high tides and two low tides each day and marked changes in water level around the harbour, river mouth and nearby shore platforms.

What makes Bay of Fundy distinctive for travellers interested in landscape and geology?

Bay of Fundy combines extreme tidal range, an ancient rift-basin origin linked to the breakup of Pangaea and cliff-lined coasts, mudflats and tidal features such as the Reversing Falls at Saint John.