Geophys. Res. Lett. doi:10.1029/2008GL036280 (2009)

In June 2008, a Japanese fishing boat, the Suwa-Maru No. 58, capsized in the Pacific in apparently moderate seas, killing 17 of the 20 crew members. The investigators conjectured that it was hit by sudden big waves.

Hitoshi Tamura and his colleagues at the Japan Agency for Marine-Earth Science and Technology in Yokohama have reconstructed the wind and sea conditions at the time of the event in a computer model to offer a plausible account of how hitherto mysterious freak waves can form. They say that the low- and high-frequency components of ordinary ocean waves interacted to channel their energy into a narrow frequency band, creating very large-amplitude waves.