Theresa Ruiz
Many myths and legends have been written describing the Maelstrom as an ocean vortex that runs up and down the sea every day, devouring great ships and spewing them up again. Authors such as Jules Verne, Edgar Allan Poe and Petter Dass write about a "current, which howls or rumbles like a buffalo herd on the prairie, that drags ships under and smashes them against the sea bed." It is this description as "the most dangerous stretch of sea" that inspired me to investigate what causes this phenomenon.
The Maelstrom is one of the world’s strongest tidal currents that creates large whirlpools or eddies midway between high and low tide. The Lofoten Maelstrom is located off the northwest coast of Norway at 67 deg. 48 min. N, 12 deg. 50 min. E between The Lofoten Point and the island Værøy southwest of the main chain of The Lofoten Islands. The strait between the islands is about 4 to 5 kilometers across, 40 to 60 meters deep, and is considerably shallower than the surrounding sea. The tide fills up the Vestfjord twice a day, and the difference in height between high and low tides can be up to 4 meters.
The word tide is defined as the alternating rise and fall in sea level with respect to the land, or put another way, the vertical change in height of the sea surface, produced by the gravitational attraction of the moon and the sun. The most familiar evidence of the tide is the observed recurrence of high and low water along our seashores. The term tidal current then refers to the accompanying horizontal movement of the ocean water. The Maelstrom is a reversing tidal current, which moves into and out of restricted passages, or more precisely the strait between the islands. This current has been said to reach speeds of up to 20 nautical miles per hour.
Accompanying these tidal currents midway between the high and low tide, as the current changes direction, eddies or whirlpools are formed. These whirlpools are created when the water encounters resistance with a landmass or water with different properties. As the current meets this resistance, smaller currents break off from the main flow and become their own independent rotating structures. These whirlpools reach proportions of up to 10 meters in diameter and 4 to 5 meters in depth, with speeds of up to 6 nautical miles per hour.
Although the Maelstrom can pose a possible danger to small ships, it is a great source of livelihood for the people of the Lofoten Islands because of the great numbers of fish that accompany it. The Maelstrom currents and whirlpools fill the strait with cold nutrient-rich water, containing plankton that the fish come to feed on. The occupants of the islands then fish the area after the Maelstrom occurrence has passed through, and bring in great numbers of catch for the day. On a side note, the Maelstrom is also a source for tourism for the islands, and many companies now offer tours by small boat to pass through the strait.
http://www.lofoten-info.no/history.htm
http://www.oceansonline.net/lobsterpage/tides/currents.html