From above, rivers that flow into the Bay of Fundy look a bit different than most. Their waters are often chocolate-colored, swirling with eddies, and bordered by red dunes and sandbars.
On the afternoon of October 20, 2019, the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite captured this image of sediment-rich water in the Bay of Fundy, the Shubenacadie River, and other nearby waterways in far eastern Canada. On land, fall weather had transformed the foliage of hardwoods and other deciduous trees and shrubs.
Sediment-rich waters are a common sight in the Bay of Fundy. With a tidal range up to 12 meters (38 feet), the funnel-shaped bay has the highest observed tides in the world. For comparison, most of the U.S. coast has a tidal range of 1 to 2 meters (3 to 6 feet).
The geometry of the bay causes tidal resonance, which plays a key role in elevating tides. The bay is just the right width and depth for water to slosh back and forth at a frequency—every 12 or 13 hours—that matches the natural frequency of high tides, which are driven by the gravitational pull of the Moon and Sun on Earth. In addition, the position and configuration of continents in the Northern Hemisphere contributes to the high tides. Since North America, Europe, and Asia are pressed closer together than the continents in the Southern Hemisphere, water gets “constricted” in the Northern Hemisphere in a way that slightly amplifies tides.
Since the Bay of Fundy becomes shallower and narrower, incoming tidal flows get forced especially high as water piles up behind mudflats at the mouth of the bay. Once water pushes past this obstacle, it rushes into the narrow valleys and collides with river water flowing in the opposite direction, producing waves and rapids that move opposite of the rivers’ natural flow.
The huge volumes of water rushing into Bay of Fundy’s feeder rivers can create quite a spectacle, with surges of water that rush upstream at roughly 15 kilometers (9 miles) per hour. They make a roaring sound reminiscent of an oncoming train. These tidal bores often have leading waves as high as 1 meter (3 feet), large enough for rafting and surfing.
As for the colors, rivers in Nova Scotia and New Brunswick flow through soft red Triassic-era sandstone that easily erodes. The sediment and the regular churning of incoming and outgoing tides and tidal bores keeps the bay and rivers perpetually muddy.
NASA Earth Observatory image by Joshua Stevens, using data from the Level 1 and Atmospheres Active Distribution System (LAADS) and Land Atmosphere Near real-time Capability for EOS (LANCE). Story by Adam Voiland.
FAQs
The Bay of Fundy has the largest tidal range in the world. Every six hours the tide can swing up to 50 vertical feet exposing or submerging large fields of mud and rocks.
What is so crazy about the tides in the Bay of Fundy? ›
Fundy's tides are the highest in the world because of an unusual combination of resonance (or seiche) and the shape of the bay. Like water in any basin, the water in the Bay of Fundy has a natural rocking motion called a seiche. You could compare this to the movement of water in a bathtub.
What are the giant tides in Fundy? ›
Tidal changes on the Bay of Fundy typically range 14.5 metres (47.6 feet) from high tide to low tide however, tidal changes in the Bay of Fundy have been measured in extreme conditions at 16.3 metres (53.5 feet).
Why is the Bay of Fundy so muddy? ›
The tide comes in nearly an hour later each day because of the changing position of the Moon around the Earth. The waters in the Minas Basin appear muddy because the tidal currents cause erosion of the red soils which become suspended in the water.
What explains the extreme tidal bore in the Bay of Fundy? ›
The tidal bore is a rare tidal phenomenon that occurs in only a few locations around the world. During a tidal bore, a standing wave of water occurs at the front of the incoming tide. This wave travels upstream at speeds that can reach 15km per hour and against the natural current in the Bay of Fundy.
Where is the most extreme tide on Earth? ›
The highest tides in the world can be found in Canada's Bay of Fundy at Burntcoat Head in Nova Scotia. Image credit: Shawn M. Kent. The highest tides in the world can be found in Canada at the Bay of Fundy, which separates New Brunswick from Nova Scotia.
How deep are the tides in the Bay of Fundy? ›
The average tidal range of all oceans around the globe is 1 meter (3ft), so how can the tidal difference in the Bay of Fundy reach up to 16 meters? This tidal phenomenon exists because the bay has a few distinct features: a substantial amount of water and a unique shape and size that causes resonance.
What is so special about the Bay of Fundy? ›
Located off the northern coast of Maine and extending into Canada between New Brunswick and Nova Scotia, the natural phenomenon known as the Bay of Fundy is a 270 km (170 mile) long ocean bay that's home to the world's highest tides (54 feet/16m).
What can be found on the ocean floor in the Bay of Fundy at low tide? ›
When the Bay of Fundy's massive tides recede, they leave behind a vast intertidal zone – endless mudflats where a wide variety of sea creatures make their home. Pick your way through fields of mud, sand and seaweed to discover barnacles, rock crabs, dog whelk sea snails, limpets, periwinkles and other crustaceans.
How fast are tides in Bay of Fundy? ›
The Bay of Fundy
The horizontal range can be as much as 5 kilometres, exposing vast areas of ocean floor. The tidal currents in the Bay of Fundy are fast, exceeding 10 knots (5 m/s, or 18 km/hr) at peak surface speed.
As for the colors, rivers in Nova Scotia and New Brunswick flow through soft red Triassic-era sandstone that easily erodes. The sediment and the regular churning of incoming and outgoing tides and tidal bores keeps the bay and rivers perpetually muddy.
Is the Bay of Fundy salt or freshwater? ›
The Bay of Fundy is filled with saltwater. Its famous tides are supplied by the Atlantic Ocean. This saltwater erodes the rocks and formations around the bay, resulting in some very unique and incredible shapes.
Can you swim at Fundy National Park? ›
Unsupervised Swimming
Swimming is unsupervised in rivers and lakes. For supervised swimming please visit the heated saltwater swimming pool.
What is the largest tidal bore in the world? ›
This is a consequence of high tidal ranges occurring in several locations around the British Isles – three rivers with notable bores are the Severn, Dee and Mersey. However, the world's largest tidal river bore is on the Qiantang River in south-east China.
How fast does the tidal bore move? ›
The roar of the tidal wave can be heard for hours before it bores up the river. The leading edge of the Qiantang River tidal bore can move as fast as 40 kilometers (25 miles) per hour. The tide behind the wave makes the river's water rise for hours after the bore passes.
What is the difference between a tidal wave and a tidal bore? ›
A tidal bore occurs along a coast where a river empties into an ocean or sea. A tidal bore is a strong tide that pushes up the river, against the current. A tidal bore is a true tidal wave.
Why does the Bay of Fundy experience drastic tidal ranges? ›
The natural period of oscillation in the Bay of Fundy is approximately 12 hours, which is also about the same length of time for one tidal oscillation (a high/low tide cycle). This coinciding of the tide cycle and the bay oscillation period results in the much larger tidal ranges observed in the bay.
What are the tidal phenomena of the Bay of Fundy? ›
The tides here have the greatest shift in the world — up to 50 feet every 6 hours and 13 minutes. That's higher than a four-story building. The tide recedes at the Hopewell Rocks. During a 12-hour period, 100 billion tons of water flow in and out of the bay.
Why is the Bay of Fundy a natural wonder? ›
Bay of Fundy has the worlds highest tidal range. Bay of Fundy is known for having the rarest whales in the world, the highest tides on earth and for being scattered with dinosaur fossils. In 2014 experts made Bay of Fundy one of the natural wonders of the world.
