“…The occurrence of extreme waves (also known as freak or rogue waves) has an important role in many branches of physics and engineering (see, for example, Chabchoub et al, 2011;Onorato et al, 2013a, b;Chalikov, 2009;Babanin et al, 2011;Bitner-Gregersen and Toffoli, 2012;Toffoli et al, 2008b;Solli et al, 2007;Kibler et al, 2010;Bailung et al, 2011, among many others). Apart from a linear superposition of wave modes and the effect of currents on waves (caustic theory), the modulational instability of a plane wave to side band perturbations remains the most plausible mechanism for the formation of rogue waves in deep water (Zakharov and Ostrovsky, 2009;Osborne, 2010;Onorato et al, 2013b;Kharif et al, 2009), i.e.…”