The great storm of 1862… swept the sea over the north end of the island of Stroma… and redistributed the ruin heaps there.
The waves ran bodily up and over the vertical cliffs on the west side, 200 feet in height, loading portions of wrecked boats, stones, seaweeds etc. on the top.
They rushed in torrents across the island, tearing up the ground and rocks in their course…..

C. W. Peach in Geikie (1887)

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.

1995. The QE2 encounters a hurricane on a crossing to New York. She takes a 29-metre wave over her bow. “It looked as if we were going into the White Cliffs of Dover,” says Captain Ronald Warwick.

1998. Schiehallion, a BP Amoco floating production platform, is struck by a wave which smashes the fo’c’sle 18m above the waterline.

Records of extreme North Sea waves

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.

Orkney 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 two decades.

Large parts of the Atlantic seabed around Orkney lie at depths of greater than 100m. To the west  the significant wave 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. 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). Extreme waves are usually associated with intense winter storms. The highest waves approach` from between northwest and west.

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.

  • The outer coast of Orkney is an outstanding location to study the erosion of hard rock coasts. Evidence of major erosion is not hard to find. The great bowl of Enegars corrie is losing its edge to the sea. The egg-shaped headland of Marwick Head is a dome half lost.

  • Amongst the many beauties of Orkney are the beaches which fringe the bays and ayres of the inner coast. These are dynamic forms, changing shape with the seasons and gradually retreating landward as sea level rises.

  • Orkney is a dissected landmass drowned by postglacial sea level rise. A drop in sea level of just 35 m would unite the archipelago into a single island. The individual islands may represent hills that formed the watershed areas of preglacial drainage basins but it is linear glacial erosion which has separated one island from another and severed Orkney from the rest of Scotland.

  • World coasts have seen sea-level variation of approximately 100 metres within the past 11,500 years through melting of the ice caps. When the ice caps melt the sea level rises globally (eustatically). The relative sea-level at any location is measured proportionate to the nearby land, which is itself subject to tectonic movement both up and down.