Seymour Narrows is a section of the Discovery Passage in

British Columbia British Columbia is the westernmost Provinces and territories of Canada, province of Canada. Situated in the Pacific Northwest between the Pacific Ocean and the Rocky Mountains, the province has a diverse geography, with rugged landscapes that ...

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 province of British Columbia. The island is in length, in width at its widest point, and in total area, while are of land. The island is the largest ...

at Menzies Bay, British Columbia and Quadra Island except at its northern end where the eastern shoreline is Sonora Island. 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 () 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 of Washington (state), Wash ...

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 o ...

from 1844 to 1848. Seymour Narrows was described by Captain

George Vancouver Captain (Royal Navy), Captain George Vancouver (; 22 June 1757 – 10 May 1798) was a Royal Navy officer and explorer best known for leading the Vancouver Expedition, which explored and charted North America's northwestern West Coast of the Uni ...

as "one of the vilest stretches of water in the world." Even after Ripple Rock 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 dynamics, the Reynolds number () is a dimensionless quantity that helps predict fluid flow patterns in different situations by measuring the ratio between Inertia, inertial and viscous forces. At low Reynolds numbers, flows tend to ...

of about

10^8

, i.e. one hundred million, 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.Environmental History and Features of Puget Sound
, NOAA-NWFSC

Ripple Rock

Ripple Rock was a submerged twin-peak 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 2H

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 ex ...

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

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 cit ...

band The Evaporators wrote a song about the event and released it on their 2004 album '' Ripple Rock''.

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 {{BritishColumbiaCentralCoast-geo-stub