Extreme wave events in the Gulf of Tehuantepec

Observations of extreme, “freak” or “rogue waves” have typically depended on chance observations from ships at sea or from fixed oil or gas platforms. The observations have been so sparse that there are very few direct temporal or spatial measurements, and those that do exist are so infrequent that they have often been individually named: e.g. the “Draupner Wave.” Such named observations tend to occur every few years. This paucity of data, and the fact that much of it is from fixed platforms, whose location is not optimized for wave research, makes it very difficult to undertake an organized study of the statistics and occurrence of rogue waves over large regions. In this paper we present an alternative approach that uses airborne spatio-temporal wave measurements, along with video imaging, to measure the evolution of waves under strong winds in fetchlimited conditions. Using the criterion that a freak wave has a height H ≥ 2Hs, where Hs is the significant wave height, during a flight of approximately 8 hours over a 400 km fetch in winds approaching 25 m s−1 in the Gulf of Tehuantepec off the Pacific coast of Mexico, we find four freak waves. We describe their spatial structure and the occurrence of breaking.