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Canada • Bay Of Fundy
• Petitcodiac (2)
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Mexico
• Colorado (5) U.S.A • Turnagain Arm (1)
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North America
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There are only five locations in North America where bores are logistically possible - the Bay Of Fundy, Baffin Islands and Hudson Bay (in Canada), Southern Alaska (in U.S.A.) and the Gulf Of California (in Mexico). These are the only regions where coastal tidal ranges exceed four metres (a necessity for a visible bore occurance).
The most significant bores occur in the Turnagain Arm (Alaska) and the Bay Of Fundy (Canada).
The Bay of Fundy in Canada divides the peninsula of Nova Scotia from New Brunswick. The Bay divides into two arms of water at the north-east end - Chignecto Bay and The Minas Basin. Because of the anticlockwise rotation of the earth, the tides are larger in the Minas Basin. Burncoat Head, Nova Scotia, has the largest tidal range in the world with a mean spring range of 14.5m (47.5ft)! And the mid-tide flow in the vast Minas Basin entrance channel, north of Cape Split, equals the combined flow of all the streams and rivers on earth!
Most of the Bay Of Fundy rivers have a bore of varying magnitude. The Petitcodiac flowing into Chignecto Bay has the largest bore in New Brunswick. Likewise the Salmon and Schubenacadie at the north-east end of the Minas Basin in Nova Scotia.
At the southern end of the Basin small bores can be found on the St Croix and Meander rivers near Windsor. There is a 'Tidal View Farm' for the St Croix at Miller Creek, approx 20km from Windsor (ETA 195min after low tide) and the Meander River Bridge between Sweets Corner and Mantua is a good viewing location (ETA 225min after low tide).
A small bore also forms at Amherst Point on the Nova Scotia side of Chignecto Bay in Cumberland Basin estuary. The wave forms near the confluence of the Maccan and Hebert rivers and travels as far as Athol on the Maccan.
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The Petitcodiac has probably the most researched tidal bore in Canada though not the largest. Dam construction has reduced the average bore height to around a foot (0.3m) although there is talk of removing the dam to restore the wave!
The river flows into Shepody Bay at the north-west end of Chignecto Bay in New Brunswick. At mean low water the river is virtually dry. Then it rises as much as 7.5m (25ft) within an hour as the tide passes! |
The bore's course takes it through Moncton, the main centre for viewing, then about 10km further upriver. A Tidal Bore Park is located off Main Street in the town. Other viewing locations are Dieppe and Riverview.
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The Salmon flows into Cobequid Bay at the north-west tip of the Minas Basin in Nova Scotia. The tidal bore here is slightly smaller than on the nearby Schubanacadie but reaches three feet on the largest tides. A drive down the coast brings you to Burntcoat Head where a reconstructed lighthouse stands in memory of the great Saxby Tide of 1869 that rose 16.5m (54ft) - the largest tide in history! |
The bore passes through the large town of Truro probably the best place to observe it. And on Route 236 the Interpretative Center has a record of tidal bore activity for the area.
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The Schubenacadie River west of Truro has probably the largest bore in the Bay Of Fundy at the present time. The head wave has reached as high as three metres! The bore travels for about 30kms up the river estuary weaving its path along the channels bordered by sand banks. The wave does not last for long distances however! Uneven distribution of the riverbed's topography results in regular deep sections where the wave backs off and diminishes. |
There are very few access areas along the river for watching the bore. But the Schubenacadie River Runners are based in Maitland near the mouth of the estuary. They run regular trips on the river in high powered zodiac boats so you can get right along side the bore! Maitland is about 30 minutes from Truro and an hour from the capital Halifax.
At the north-west end of the Gulf is the mouth of the Colorado River. It is here that one of the largest bores in the world used to form. Sadly, the bore is now a rare (and much smaller) occurrance due to human interference up river in California and Arizona affecting the fluvial flow. The mouth of the Colorado is a fine illustration of the rapid constriction of a channel and the funnel topography necessary for a tidal bore to occur.
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The phenomenal Colorado River bore is now sadly a rare occurrance. The river discharges into the Gulf Of California. The bore formed in the river mouth around Montague Island and travelled as far as El Mayor. The head-wave is reputed to have reached almost 20 feet! Reclamation projects miles upstream in Arizona and California have all but eliminated the bore.
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Cook Inlet is unique among all the locations on our tour. Bores generally occur on rivers meandering through lowland regions. But the bores in the Inlet are surrounded by the glaciated peaks of the Chugach Range less than 2km from the waters edge! This makes for a dramatically picturesque experience.
The arms are fiords dating from the late Holocene period that have been infilled by intertidal sediment. The largest bore in North America occurs on the Turnagain Arm while the Knik Arm has a very small bore of less than a foot height.
Cook Inlet is also at the highest latitude of any documented bore (61°00'N) and hence the water temperature never rises above 8°C! The tidal range of the Cook Inlet is the second largest in North America reaching 12.1m (40ft).
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The Turnagain Arm is a fiord just south of Anchorage at the head of the Cook Inlet. The Arm is about 20 miles long and between one and two miles wide. Although at low tide much of the upper arm is dry, there are multiple complex channels with water at all times. The wave runs the entire length of the Arm, but backs off occassionally. From Anchorage, the Seaward Highway runs alongside the arm for about 50 miles, so it is possible to track the bore.
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The Arm is filled with silty, glacier fed, salt water, which only gets to a maximum of 7.5°C (45°F) in summer! In winter when the Arm is full of ice the bore reaches upto 8m/s (20mph) as it is channeled down by the ice.
Kayakers have been riding the bore for over 15 years, but it is only in the last couple that a group of five surfers have taken it on and on October 21st 1998, Lolly Moss became the first (and only) woman to surf the Arm.
6mm hooded steamers or dry suits are necessary. There are lots of icebergs and slushy ice to dodge in the water. It is also possible to ride one of the undular swells trailing the head wave. This daring water rodeo has been dubbed
The Bore Tide Follies!
A popular viewing location for the bore is at Bird Point. The bore tide appears in the Arm about 2 hours after low tide at Anchorage.