Why the Bay of Fundy Has the World's Highest Tides

The Bay of Fundy (between New Brunswick and Nova Scotia, Canada) experiences tidal ranges up to 17 m (56 ft)—the highest on Earth. Three factors resonate to create this extreme:

1. Basin Geometry (The Funnel)

The bay is 280 km long, narrowing from 80 km to 14 km wide, with a shoaling bottom. This shape acts as a natural funnel: incoming tidal water is squeezed horizontally and vertically, amplifying height.

2. Resonance (Seiche)

The bay's natural oscillation period (~12.4 hours) nearly matches the lunar semi-diurnal tide (M2, 12.42 hr). Like pushing a swing at the right rhythm, each tidal pulse reinforces the next. This near-resonance amplifies the tidal range 2–3x over the open ocean.

3. Coriolis Effect & Earth's Rotation

In the Northern Hemisphere, the Coriolis force deflects moving water to the right. In the bay, this drives a counter-clockwise gyre, piling water against the northern (NB) shore, further increasing range there (e.g., Burntcoat Head, 17 m).

4. Gravitational Forcing (Moon & Sun)

Standard lunar/solar tide-generating forces provide the energy input. Spring tides (new/full moon) + resonance = extreme highs. Perigean spring tides ("king tides") + storm surge = record events.

Resulting Phenomena

• Tidal Bore: Advancing tide forms a wave up the Petitcodiac and Salmon Rivers (surfable).
• Reversing Falls (Saint John, NB): Rapids reverse direction with tide.
• Intertidal Zone: Vast mudflats exposed → critical shorebird habitat (Semipalmated Sandpiper migration).
• Tidal Power: Annapolis Royal Generating Station (20 MW, 1984–2019); new in-stream turbine projects.

The Bay of Fundy is a resonant tidal amplifier—geography and astronomy in perfect sync.