If you look online, the term “rogue wave” gets thrown around a lot – a whole lot. And most of the videos you see of “rogue waves”, “freak waves”, and “monster waves” are just, in fact, big waves. What makes a deep-water ocean wave a rogue, scientifically speaking, is that it is extreme compared to its surroundings. One definition requires that a rogue wave be more than twice as tall as the height of average large waves in the area – like the rogue that takes out the Lego boat above. Outside the lab, this is a rare event – fortunately – because a true rogue wave has tremendous destructive power and seems to appear out of the blue.
This seemingly unpredictable behavior is thought to arise from nonlinear interactions between waves. Essentially, under the right conditions, a rogue wave grows monstrously large by sucking energy out of other surrounding waves. One way to try and predict rogue waves is to measure all the waves nearby and simulate their potential nonlinear interactions computationally – but this is time-consuming and requires a lot of computing power.
Instead, researchers have developed an alternative method, illustrated in the time series above. Instead of considering the rogue potential for all waves, they identify waves with characteristics that make them more likely to go rogue and focus on simulating those waves. In the animation, the wave packets are colored from green to red based on their increasing likelihood of turning into rogue waves. The algorithm is simple enough to run quickly on a laptop and can provide a couple minutes of warning to a ship’s crew – enough time to batten down before the wave hits. (Image credits: simulation – T. Sapsis et al., source; experiment: N. Ahkmediev et al., source; via The Economist and MIT News; submitted by 1307phaezr)