Columbia River bar

The Columbia Bar, also frequently called the Columbia River Bar, is a system of bars and shoals at the mouth of the Columbia River spanning the U.S. states of Oregon and Washington. The bar is about 3 miles (5 km) wide and 6 miles (10 km) long.

The bar is where the river's current dissipates into the Pacific Ocean, often as large standing waves. The waves are partially caused by the deposition of sediment as the river slows, as well as mixing with ocean waves. The waves, wind, and current are hazardous for vessels of all sizes. The Columbia current varies from 4 to 7 knots westward, and therefore into the predominantly westerly winds and ocean swells, creating significant surface conditions. Unlike other major rivers, the current is focused "like a fire hose" without the benefit of a river delta. Conditions can change from calm to life-threatening in as little as five minutes due to changes of direction of wind and ocean swell. Since 1792, approximately 2,000 large ships have sunk in and around the Columbia Bar, and because of the danger and the numerous shipwrecks the mouth of the Columbia River acquired a reputation worldwide as the Graveyard of the Pacific.

The navigational channel is 2,640 feet (800 m) wide at the west end and narrows to 600 feet (180 m) within the jetties (though the jetties themselves are never closer than two miles apart). The channel is dredged to 55 feet (17 m) in the northern three-quarters and 48 feet (15 m) for the southern quarter. Inside the bar, the channel remains 600 feet (180 m) wide and reduces to 43 feet (13 m) deep.

The nearby United States Coast Guard Station Cape Disappointment, Washington, is renowned for operating in some of the roughest sea conditions in the world, and is home to the National Motor Lifeboat School. It is the only school for rough weather and surf rescue operation in the US, and is respected internationally as a center of excellence for heavy boat operations.

Approximately 16 bar pilots, earning about $180,000 per year, guide ships across the bar, often boarding ships by helicopter. They generally consider "the bar" to be the area between the north and south jetties and Sand Island (see detail of bathymetric map for locations of these).

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Wikipedia