Seymour Narrows is a section of the

Discovery Passage , image = Discovery Passage.jpg , image_size = 250px , caption = Looking south from between Vancouver Island and Sonora Island , image_bathymetry = Locmap-DiscoveryPassage.png , caption_bathymetry = , loc ...

British Columbia British Columbia (commonly abbreviated as BC) is the westernmost province of Canada, situated between the Pacific Ocean and the Rocky Mountains. It has a diverse geography, with rugged landscapes that include rocky coastlines, sandy beaches, ...

known for strong tidal currents. Discovery Passage lies between

Vancouver Island Vancouver Island is an island in the northeastern Pacific Ocean and part of the Canadian Provinces and territories of Canada, province of British Columbia. The island is in length, in width at its widest point, and in total area, while are o ...

at Menzies Bay, British Columbia and

Quadra Island Quadra Island is a large island off the eastern coast of Vancouver Island, in British Columbia, Canada. It is part of the Discovery Islands, in the Strathcona Regional District. Etymology In 1903, the island was named after the Peruvian Spanish n ...

except at its northern end where the eastern shoreline is

Sonora Island Sonora Island is one of the outer islands (without ferry service) of the Discovery Islands of British Columbia, Canada. It is located at the eastern end of Johnstone Strait and the northern end of Discovery Passage within Electoral Area C of the ...

. The section known as Seymour Narrows begins about from the south end of Discovery Passage where it enters the

Georgia Strait The Strait of Georgia (french: Détroit de Géorgie) or the Georgia Strait is an arm of the Salish Sea between Vancouver Island and the extreme southwestern mainland coast of British Columbia, Canada and the extreme northwestern mainland coast ...

near Campbell River. For most of the length of the narrows, the channel is about wide. Through this narrow channel, currents can reach .

Etymology

The narrows were named for Rear Admiral Sir George Francis Seymour who commanded the

Pacific Station The Pacific Station was created in 1837 as one of the geographical military formations into which the Royal Navy divided its worldwide responsibilities. The South America Station was split into the Pacific Station and the South East Coast of A ...

from 1844 to 1848. Seymour Narrows was described by Captain

George Vancouver Captain George Vancouver (22 June 1757 – 10 May 1798) was a British Royal Navy officer best known for his 1791–1795 expedition, which explored and charted North America's northwestern Pacific Coast regions, including the coasts of what a ...

as "one of the vilest stretches of water in the world."B.C.'s deadly Ripple Rock blown up, CBC Broadcast Date: April 5, 1958
/ref> Even after

Ripple Rock Ripple Rock (french: Roche Ripple) is an underwater mountain located in the Seymour Narrows of the Discovery Passage in British Columbia, Canada. It had two peaks (2.74 metres and 6.4 metres below the surface at low tide) that produced large, d ...

was removed, it remains a challenging route. In March 1981, the freighter ''Star Philippine'' ran aground in the narrows.

Hydrology

Seymour Narrows is notable also because the flowing current can be sufficiently turbulent to realize a

Reynolds number In fluid mechanics, the Reynolds number () is a dimensionless quantity that helps predict fluid flow patterns in different situations by measuring the ratio between inertial and viscous forces. At low Reynolds numbers, flows tend to be domi ...

of about

10^9

, i.e. one billion, which is possibly the largest Reynolds number regularly attained in natural water channels on Earth (the current speed is about , the nominal depth about ). Turbulence develops usually around a Reynolds number of 2000, depending on the geometric structure of the channel. Seymour Narrows delineates part of the northern extent of the

Salish Sea , image = PNW-straits.jpg , alt = , caption = The Salish Sea, showing the open Pacific Ocean at lower left, and from there, heading inland: the Strait of Juan de Fuca, the narrow Puget Sound at lower ri ...

.Environmental History and Features of Puget Sound
, NOAA-NWFSC

Ripple Rock

Ripple Rock was a submerged

twin-peak A double summit, double peak, twin summit, or twin peak refers to a mountain or hill that has two summits, separated by a col or saddle. One well-known double summit is Austria’s highest mountain, the Großglockner, where the main summit of t ...

mountain that lay just nine feet beneath the surface of Seymour Narrows. It was a serious hazard to shipping, sinking 119 vessels and taking 114 lives. The gunboat USS ''Saranac'' was one of the rock's first recorded victims. On April 5, 1958, after twenty-seven months of tunneling and engineering work, Ripple Rock was blown up with 1,375 tons of

Nitramex Nitramex and Nitramon Explosives are compositions of various chemical compounds. They are explosives based on ammonium nitrate, with other ingredients such as paraffin wax, aluminum and dinitrotoluene. The inclusion of these additional ingredients ...

explosive An explosive (or explosive material) is a reactive substance that contains a great amount of potential energy that can produce an explosion if released suddenly, usually accompanied by the production of light, heat, sound, and pressure. An expl ...

making it the largest commercial, non-nuclear blast in North America. The

Halifax Explosion On the morning of 6 December 1917, the French cargo ship collided with the Norwegian vessel in the waters of Halifax, Nova Scotia, Canada. The ''Mont-Blanc'', laden with high explosives, caught fire and exploded, devastating the Richmond ...

in 1917 was larger but it was not a deliberate act. The event was broadcast live on Canadian television. The footage is also regularly screened at the

Campbell River Museum Campbell may refer to: People Surname * Campbell (surname), includes a list of people with surname Campbell Given name * Campbell Brown (footballer), an Australian rules footballer * Campbell Brown (journalist) (born 1968), American television n ...

Vancouver Vancouver ( ) is a major city in western Canada, located in the Lower Mainland region of British Columbia. As the List of cities in British Columbia, most populous city in the province, the 2021 Canadian census recorded 662,248 people in the ...

band

The Evaporators The Evaporators is a Canadian garage rock band formed in 1986 in Vancouver, British Columbia. Nardwuar, its founding member, is also known for interviewing musicians and celebrities. As of 2007, the band consists of vocalist/keyboardist Nardwuar ...

wrote a song about the event and released it on their 2004 album ''

''.

References

Canadian Tide and Current Tables, Vol. 6, 2003

External links

Overview of Seymour Narrows
Archived fro

on 2012-02-05

Ripple Rock blown up – Unforgettable Moments – CBC Archives
(Video)
Campbell River Museum official website

Navigating Seymour Narrows
* ''Freighter Aground in Canada'', in the New York Times, March 18, 1981 Central Coast of British Columbia Landforms of the Discovery Islands Straits of British Columbia {{BritishColumbiaCoast-geo-stub