Lighthouse builder, David Stevenson, described how in 1842 a block weighing 6 tons was moved at 80’ asl during the construction of the light on Muckle Flugga
Records of extreme North Atlantic waves
1966. Italian steamship Michelangelo is hit by a
21-metre wave en route to New York. The water smashes through the
bridge and into the first class compartments, killing two
passengers and a crew member.
2000. A British
oceanographic research vessel near Rockall, west of Scotland
experienced the largest waves ever recorded by scientific
instruments in the open ocean. Under severe gale force
conditions with wind speeds averaging 21 ms−1 a shipborne wave
recorder measured individual waves up to 29.1 m from crest to
1995, North Sea. Statoil floating rig Veslefrikk B is severely damaged by a rogue wave. One crew member describes a "wall of water" visible for several minutes before it strikes.
1995, North Sea. Hogmanay wave at Statoil's Draupner field measured at 26 m from trough to crest.
“Yet in the Bound Skerry of Whalsey, the breakers have torn up masses of rock sometimes 8˝ tons in weight, and have heaped them together at a height of no less than 62 feet above high-water mark. Other blocks, ranging in bulk from 6 to 13˝ tons, have been actually been quarried out of their place in situ at levels from 70 to 74 feet above the sea.
Archibald Geikie (1887) describing Bound Skerry on Out Skerries (HU 702719)
Shetland experiences one of the highest wave energy environments in the world. The west coast is exposed to the full force of the Atlantic waves, with hundreds of kilometres of fetch, hurricane-force wind speeds and deep water close inshore allowing huge waves to arrive at the cliffs unbroken. The outer parts of the east coast must also experience some very large waves, as oil rigs in the northern North Sea has recorded some monsters over the last decade.
Dore Holm, January 1989. The upper line gives the spray zone; the lower the splash height. The summit of Dore Holm lies at 36 m asl. Image courtesy of the Tangwick Haa Museum
Large parts of the seabed around the Shetland Islands lie at depths of greater than 100m. To the west of Shetland the significant wave height is
The mean or average height of the highest one third of all waves in a swell train or in a wave generating region. It also approximates the value an experienced observer would report if visually estimating sea height
exceeded for 10% of the year is about 4m, reducing to about 3m to the east of Shetland (JNCC, 1997). Variations can be extreme and in 1996, 26% of all waves exceeded 4m, whilst in February 1997 89% of all waves exceeded 4m.
Annual maximum storm wave height in the North Atlantic
During storms much higher waves are common. To the east of Shetland waves reached 18.5m in 1969 at 560N, 40W (Burridge, 1973). To the west of Shetland storm waves reached 15.13m at 600N, 40W in January 1974 (Marex, 1975), 24.4m at 590N, 190W (Draper and Squire, 1967) and 15m in 1997 (Met Office, 1997). The occurrence of extreme waves is subject to a distinct November - March winter bias. The highest waves approach from between north and southwest.
There is an increasing amount of evidence to suggest an increase over recent decades of wave heights in the North Atlantic. The Waves and Storms in the North Atlantic (WASA) project used a combination of modelling and observational data to report increases in wave height of 2.5-7.5mma-1 over the period 1955-94 (Gunther et al, 1998). This is supported by the observational data of Gulev and Hasse (1999), who indicate a 1-3mma-1 increase in North Atlantic wave height in the last 30 years, possibly linked to intensification of the North Atlantic Oscillation (NOA). If this is the case then there appears to be little reason to suggest that the maximum heights achieved by extreme waves should not also be subject to a similar increase over time.