A bigger splash

click photo to enlarge

All waves are not equal. Some are bigger than others. Everyone knows about the tsunami, a wave triggered by an undersea earthquake. But fewer are aware of the "rogue" or "freak" wave that can suddenly appear and sink even the largest ship.

Such waves are legendary, but until recently scientists dismissed such reports, counting them alongside stories of mermaids and sea monsters. Now, however, there is ample evidence of their existence from photographs and radar satellites, It is common for mid-ocean storms to have waves 7m high, and exceptional waves reaching 15m. However, ships and oil platforms have now measured "rogues" twice this height - up to 30m. A ship encountering the trough preceding a rogue wave can expect to be hit by a wall of water bearing down with a force of 100 tonnes/sq m. Marine architects routinely construct ships to withstand 15-20 tonnes/sq m. In an encounter with the same rogue wave in the South Atlantic in 2004 the "Bremen" and the "Caledonian Star" had their bridge windows 30m above the sea smashed, and lost all power and instruments. The unexplained loss of many ships is now felt to be the consequence of meeting one of these giants.

The wave in my photograph is not a rogue - they are creatures of the deep sea. But it was an unexpectedly large one. The couple on the promenade had been lulled into a false sense of security by the smaller waves that had been breaking at a lower level. You can guess what happened next! The concave sea wall tried to turn the wave back, but the strong onshore wind had other ideas! They were too slow to get out of the way, and got soaked. I took my photograph from a higher part of the promenade, shooting against the light with a long zoom lens at 86mm (35mm equivalent). The camera was set to Aperture Priority (f6.3 at 1/4,000 sec), ISO 200, with -1.7EV.

photograph & text (c) T. Boughen