Definition(s)
Wave Steepness
Characteristic of individual waves calculated as wave height divided by wave length.
NOTE For periodic waves, the concept is straightforward as H/λ. For random waves, the definition is used with the significant wave height (Hs) and the wave length that corresponds with the peak period (Tp) of the wave spectrum in deep water. The significant wave steepness is then defined as Hs/λp = Hs / [(g/2π) Tp2] and is typically in the range of 1/16 to 1/20 for severe sea states.
Source: API RP 2MET, Derivation of Metocean Design and Operating Conditions, First Edition, November 2014. Global Standards