Seymour Narrows

Seymour Narrows is a 5 km (3.1 mi) section of the Discovery Passage in British Columbia known for strong tidal currents. Discovery Passage lies between Vancouver Island 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 18 km (11 mi) from the south end of Discovery Passage where it enters the Georgia Strait near Campbell River. For most of the length of the narrows, the channel is about 750 m wide. Through this narrow channel, currents can reach 15 kn.

Seymour Narrows was described by Captain George Vancouver 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 Star Philippine, a freighter, ran aground in the narrows.

Seymour Narrows is notable also because the flowing current can be sufficiently turbulent to realize a Reynolds number of about , i.e. one billion, which is possibly the largest Reynolds number regularly attained in natural water channels on Earth (the current speed is about 8 m/s, the nominal depth about 100 m). Turbulence develops usually around a Reynolds number of 2000, depending on the geometric structure of the channel.

Ripple Rock

Coordinates: 50°08.2′N 125°21.2′W / 50.1367°N 125.3533°W / 50.1367; -125.3533 Ripple Rock is an underwater mountain that had two peaks (9 feet and 21 feet below the surface) in the Seymour Narrows of the Discovery Passage in British Columbia, Canada, a part of the marine trade route from Vancouver and coastal points north. The nearest town is Campbell River. Only 2.7 metres (9 feet) underwater at low tide, it was a marine hazard in what the explorer George Vancouver described as "one of the vilest stretches of water in the world." The hazard was not only hitting the rock but also big, dangerous eddies caused by tidal currents round the rock. Ships using the strait preferred to wait until slack tide.

Its top was removed by a planned explosion on 5 April 1958. This is a National Historic Event in Canada. The Ripple Rock explosion was seen throughout Canada, live on CBC Television. It was one of the first live coast-to-coast television broadcasts of an event in Canada.

It was so named in 1860 by Captain Richards, RN, because its summits were about at sea level and made a prominent standing wave in the fast tidal current of the strait.

British Columbia

British Columbia, also commonly referred to by its initials BC, is a province located on the west coast of Canada. British Columbia is also a component of the Pacific Northwest and the Cascadia bioregion, along with the US states of Idaho, Oregon, Washington and Alaska The province's name was chosen in 1858 by members of the Hudson's Bay Company. In 1871, it became the sixth province of Canada. Its Latin motto is Splendor sine occasu ("Splendour without Diminishment").

The capital of British Columbia is Victoria, the fifteenth-largest metropolitan region in Canada, named for the Queen who created the Colony of British Columbia. The largest city is Vancouver, the third-largest metropolitan area in Canada, the largest in Western Canada, and the second-largest in the Pacific Northwest. In October 2013, British Columbia had an estimated population of 4,606,371 (about 2.5 million of whom were in Greater Vancouver). The province is currently governed by the BC Liberal Party, led by Premier Christy Clark, who became leader as a result of a leadership convention vote on February 26, 2011, and who led her party to an election victory on May 14, 2013.

Discovery Passage

Discovery Passage is a channel that forms part of the Inside Passage between Vancouver Island and the Discovery Islands which lie off the British Columbia coast north of the Georgia Strait. It was named by Captain Vancouver for his ship, the HMS Discovery. Most of the eastern shoreline of the passage is Quadra Island, with Sonora Island forming the shoreline at the northern end where Discovery Passage meets Johnstone Strait. The southern end of Discovery Passage enters the Strait of Georgia. It is 25 km (16 mi) in length and is typically about 2 km (1.2 mi) in width, less at Seymour Narrows which lies in the lower half of Discovery Passage.

The passage is a significant shipping route as it is the preferred channel for vessels' entering or leaving the Georgia Strait from the north. It forms a part of the Inside Passage shipping route.

See also

References

Coordinates: 50°13′N 125°23′W / 50.217°N 125.383°W / 50.217; -125.383

Narrows

A narrows is a restricted land or water passages. Most commonly a narrows is a strait, though it can also be a water gap.

A narrows may form where a stream passes through a tilted bed of hard rock lying between two softer beds: "[i]f the hard beds are vertical, so that their outcrop does not shift as erosion proceeds, a narrows is developed". Like a dam, this "raises the water level for a short distance upriver". A narrows is also typically a good location for trapping migrating fish. Furthermore, a narrows is "an important topographical feature for wind mixing", an effect where a wind chill may form ice while the surrounding temperature remains above freezing.

See also

References