Twice everyday the bay fills and empties of a billion tonnes of water during each tide cycle—that’s more than the flow of all the world’s freshwater rivers combined.
This page contains a lot of information. We encourage you to read the entire page, but if you’re just looking for some specific information you may want to use the following index to jump to the appropriate section:
- How High are the Fundy Tides?
- What Causes the Tides?
- Neap & Spring Tides
- Why are the Bay of Fundy Tides the Highest?
- When is the Best Time to Experience the Tides?
- Different Types of Tides
How High are the Fundy Tides?
The Bay of Fundy has the highest tides in the world, and those enormous tides alone make that the Bay of Fundy is one of the world’s greatest natural wonders.
The height of the tide difference ranges from 3.5 meters (11ft) along the southwest shore of Nova Scotia and steadily increases as the flood waters travel up the 280 km (174 miles) of shoreline to the head of the Bay where, in the Minas Basin, the height of the tide can reach an incredible 16 meters (53ft).
The force created by these mighty waters is equal to 8000 locomotives or 25 million horses at the Minas Channel. The immense energy of the tides stir up nutrients from the ocean floor, the mud flats and salt water marshes, providing an abundance of food for the birds, whales, fish and bottom dwellers that visit or call Fundy home.
This highly productive, rich and diverse natural ecosystem has shaped the environment, the economy and the culture of the Fundy region. The effect of the world’s highest tides on the Bay’s shores has created dramatic cliffs and awesome sea stacks. The red sandstone and volcanic rock have been worn away to reveal fossils from over 300 million years ago.
What Causes the Tides?
Tides are considered the heartbeat of our planet’s oceans. They are the periodic rise and fall of the earth’s bodies of open water, and are a result of the gravitational pull of the moon and sun on the earth, as well as the perpetual spinning rotation of the earth itself.
By far the largest influence is the gravitational effect of the moon as it pulls the water toward itself, making a bulge on the surface of the ocean at the side of the moon (lunar tide).
At the same time, the centrifugal force (caused by the spinning of the Earth-Moon system) acting on the water particles at earth’s surface opposite the moon,creates a second bulge. These bulges are what we refer to as high tide.
As the moon revolves around the earth the bulges shift with it causing a shift in the water level. It’s the combination of the speed at which the earth rotates on its own axis (once in 24 hours), and the speed at which the moon revolves around the earth (in 27.3 days), that dictate the time it takes to go from high to low tide.
Because the moon orbits in the same direction the earth rotates around its axis, it takes a little more than a day—24 hours and 53 minutes—for the earth to fully rotate in relation to the moon (i.e. where from a fixed point on earth the moon appears in the same position in the sky as a day earlier). (Kudos to Gord Steadman for providing the proper wording)
Since the effect of the moon is the same when it’s straight “above” us as when it’s straight “underneath” us, one tide cycle (from high to high, or low to low) takes half that time: about 12 hours and 26 minutes. This in turn means that the time between a high tide and a low tide (and vice versa) is, on average, six hours and 13 minutes. This explains why tides arrive at the same location almost an hour later each day.
Neap & Spring Tides
The Sun also exercises a gravitational attraction on the earth, which causes a secondary, less powerful, tidal effect (solar tide).
Approximately twice a month, the sun, moon and earth will more or less align to form either a full moon or a new moon. During each phase of a new moon or a full moon, the two tidal effects strengthen one another, resulting in higher high tides and lower low tides. These extremes are referred to as “spring tides”, a term derived from the springing up of the water.
Conversely, twice each month when the sun and moon are at right angles to the earth and opposing each other (first and third quarter moons), the tidal ranges are less than normal and are defined as “neap tides”.
Because of these periodic fluctuations in gravitational pulls from the sun and moon, the height of the tides varies from day to day. To really experience the world’s highest tides, you should visit the Bay of Fundy during a full moon cycle!
Why are the Bay of Fundy Tides the Highest?
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.
A liquid in a basin has a characteristic period of “oscillation” and, once set in motion, the liquid will rhythmically slosh back and forth in this time period. The surface rises first at one end, then at the other, while the level in the middle remains nearly constant. The speed at which it oscillates depends on the length and depth of the basin.
On a small scale, picture water sloshing around in a bathtub. It takes just seconds to slosh back and forth. Due to the enormous size, the unique funnel shape, and the immense depth of the Bay of Fundy, its natural period of oscillation is somewhere between 12 and 13 hours.
That oscillation is in perfect sync with the Atlantic ocean tide flooding into the bay every 12 hours and 26 minutes, which results in “resonance”.
Imagine someone on a swing, going back and forth, reaching the same height every time. Now imagine someone else giving the person on the swing a solid push every time the person starts to move forward again. They are obviously going to go much higher this time.
Well, the water in the Bay of Fundy is like the person on the swing and the tides coming in from the Atlantic Ocean are like the person giving the push. It’s because the water in the bay moves back and forth in sync with the oceanic tides outside that there is such a large increase in the tidal range towards the head of the Bay.
The bay’s shape and bottom topography also have a secondary influence on the tides. The bay is shaped like a large natural funnel; it becomes narrower and shallower towards the upper part of the bay, forcing the water higher up onto the shores.
When is the Best Time to Experience the Tides?
There are approximately two high tides and two low tides every 24-hour period in the Bay of Fundy. The time between a high tide and a low tide is, on average, six hours and 13 minutes. As such, visitors to the Fundy coast can realistically expect to see at least one high and one low tide during daylight hours.
One of the best ways to experience the full impression of the Bay of Fundy’s tides is to visit the same coastal location at high tide, then return about six hours later at low tide (or vice versa).
Don’t worry about missing too much in the time in between. The tide does not come in like a large 16 meter high wave, but rather gently flows and gurgles across the vast expanse of exposed mud and gravel in the intertidal zone until it’s once again under the sea.
Also keep in mind that high and low tide times move ahead approximately one hour each day, and tide times vary slightly for different locations around the Bay. It’s generally a good idea to check ahead for accurate high and low tide times.
Different Types of Tides
The world’s highest tides actually provide four different tidal effects: vertical, horizontal, rapids & rip tides, and tidal bores.
Vertical Tidal Effect
This is the tidal effect the Bay of Fundy is renowned for and entitles it as the place with the highest tides in the world. The vertical effect can be seen at most wharves around the bay.
First visit at high tide to see all the boats float level with the top of the docks. Then return 6 hours later to see the boats sitting on the ocean floor, up to 16 meters lower than where they started. That’s like lowering them from a 4- or 5-story building!
Horizontal Tidal Effect
Several beach areas at the upper parts of the Bay of Fundy showcase the horizontal tidal effect better than anywhere else in the world.
Again, you’ll need to visit the same area twice, six hours apart, to truly admire this remarkable sight. In just over six hours the tides can expose a vast expanse of ocean floor.
And for this one, you will have to stop thinking in meters or feet. The water can travel up to 5 kilometres (3 miles) away from where it was at high tide. This also means you will have to be careful when you explore the exposed ocean floor because the water can rush back in at over 10 meters per minute!
A tidal bore is a tidal phenomenon in which the leading edge of the incoming tide forms a standing wave of water that travels upstream, against the current of a river or narrow bay.
This wave can travel at speeds close to 15 km per hour (10 mph) and generates rapids in its wake that are between 3 and 3.5 meters (10-12 ft) high.
In the summer months, experienced guides take visitors on a one-of-a-kind, upriver rafting adventure. Tidal bore rafting might just be the best way to experience the Bay of Fundy tides first hand!
Tidal Rapids, Whirlpools & Rips
Because the Bay of Fundy coast consists of such rugged landscape, with cliffs and large headlands sticking out into the Bay, the flow of the 100 billion tonnes of water is anything but smooth.
Another spectacular way to see the tides is to visit a location where tidal rapids, whirlpools or rips can be seen.
The most famous whirlpool is of course the Old Sow Whirlpool, located in the Passamaquoddy Bay towards the mouth of the Bay of Fundy. Old Sow is the largest whirlpool in the western hemisphere, and the second largest in the world!
In broad overview, the amazing Fundy tides can be considered one of the world’s most natural and unspoiled wonders.
At Hopewell Rocks the tidal currents have carved and sculpted towering statues of red sandstone. Topped by evergreens, they resemble huge flowerpots and stand as one of many Fundy marvels.
At St. Martin’s, the endless tidal action has carved out spelunker perfect sea caves. And with each receding tide, vast nutrient-rich mudflats are exposed in the Minas Basin.
And underlining the fragility of nature is the certainty that with the continuous passage of time, the surging, monumental tides will ultimately destroy themselves as they slowly erode and disintegrate this unique basin.
So don’t wait any longer and plan your trip to the Bay of Fundy today!