Highest Tides on Earth

The highest tides on Earth occur in the Bay of Fundy, located on the Atlantic coast of Canada, between the provinces of New Brunswick and Nova Scotia. The tidal range in the Bay of Fundy is the largest in the world, reaching up to 16 metres (52 feet) under certain conditions. These extraordinary tides are a result of a unique combination of geography, resonance, and oceanic dynamics that amplify the normal rise and fall of sea levels caused by the gravitational pull of the Moon and the Sun.

Geographic Location

• Name: Bay of Fundy
• Location: Between New Brunswick and Nova Scotia, Canada
• Coordinates: Approximately 45°N latitude and 65°W longitude
• Connection: Opens to the Gulf of Maine and the wider Atlantic Ocean
• Length: About 270 kilometres (170 miles) long
• Width: Varies from 80 km at the mouth to only about 5 km at the head

The bay’s funnel-like shape and gradually shallowing seabed play key roles in amplifying the tidal forces that produce its extreme water level variations.

Causes of the Extreme Tides

The tidal amplitude in the Bay of Fundy results from three main factors:

1. Resonance Effect

The Bay of Fundy has a natural resonant period (the time it takes for a wave to travel from the mouth to the head and back) that nearly matches the period of the Moon’s tidal cycle, approximately 12 hours and 25 minutes.

• This resonance acts like a sloshing effect in a bathtub — the timing of the returning wave reinforces the incoming tide, creating higher and higher tidal amplitudes.

2. Shape of the Bay

• The bay’s narrow, funnel-shaped geometry causes water to be funneled and forced upward as it moves toward the bay’s head.
• The tapering coastlines and gradually shallowing seabed magnify the vertical range of the tide.

3. Large Tidal Volume

• Enormous quantities of water move in and out of the Bay of Fundy twice each day — estimated at about 100 billion tonnes (or 100 cubic kilometres) of seawater per tidal cycle.
• The constriction of this massive volume of water in a confined space amplifies tidal height.

Tidal Range Measurements

The Bay of Fundy experiences a tidal range (difference between high and low tide) that varies across different locations:

During spring tides (when the Earth, Moon, and Sun are aligned), the tidal range reaches its maximum. Conversely, during neap tides (when the Sun and Moon are at right angles), the range decreases.

Unique Phenomena in the Bay of Fundy

1. Reversing Falls (Saint John River, New Brunswick):

At the mouth of the Saint John River, the powerful incoming Fundy tides reverse the river’s flow twice daily, creating turbulent rapids and whirlpools known as the Reversing Falls.

2. Tidal Bore (Minas Basin and Shubenacadie River):

A tidal bore occurs when the incoming tide forms a fast-moving wall of water that travels upriver against the current.

• In the Shubenacadie River, tidal bores can reach speeds of up to 15 km/h (9 mph) and heights of 1–3 metres (3–10 feet).

3. Sea Cliffs and Rock Formations:

The dramatic vertical difference between high and low tides has sculpted striking coastal features such as Hopewell Rocks, where towering pillars of rock are alternately submerged and exposed by the tides.

Comparison with Other High-Tide Regions

Ecological and Environmental Importance

1. Marine Biodiversity:
   • The tidal mixing in the bay brings nutrients to the surface, supporting plankton, fish, and large marine species such as whales and seals.
   • The Bay of Fundy is an important feeding ground for humpback, fin, and right whales.
2. Tidal Energy Potential:
   • The immense tidal movement makes the region ideal for tidal power generation.
   • Experimental tidal turbines have been deployed in the Minas Passage to harness renewable energy.
3. Coastal Ecosystem:
   • The intertidal zones host rich mudflats and salt marshes, providing habitats for migratory birds, crustaceans, and fish.

Tourism and Economic Value

The Bay of Fundy attracts visitors from around the world who come to witness its phenomenal tides.

• Activities: Whale watching, tidal bore rafting, coastal hiking, and geological sightseeing.
• Key Attractions: Hopewell Rocks, Fundy National Park, and Burntcoat Head Park.
• The tidal range also supports local economies through fishing, aquaculture, and renewable energy projects.