Extreme waves

The highest observed wave in the Baltic is 14 m between crest and trough. The Finnish Institute for Marine Research registered this wave off southern Åland on 22 December 2004. The significant wave height at this time was 7.7 m. The highest wave registered off the Swedish coast is 13.0 m, again with a significant wave height of 7.7 m. This wave was registered on the west coast outside the Väderöarna islands on 14 January 2007.

In the north-eastern Baltic the risk of meeting the highest waves is greatest, since strong south-westerly winds are common and they have the longest wind fetch. High seas can start to build up south of Gotland. On the west coast the highest significant wave height was 7,7 meter and the maximum wave height 13,0 meter outside Väderöarna 14 januari 2007.

Monster waves

Extremely high rogue waves have always been reported by sailors but it is only during the latest 15 years that it has been possible to observe and monitor these monster waves. There is no simple explanation other than that the energy from several wave systems combines on unique occasions into one large wave. Monster waves have a short lifespan.

According to the Guinness Book of Records, waves with a height of 24 m were observed in the northern Pacific by the USS Ramapo on the night of 6-7 February 1933, when the average windspeed was 35 m/s.

The highest measured wave was 26 m observed by the ship Weather reporter in the Atlantic at 59° N 19° W on 30 December 1972.