Definition of Significant Wave Height

Significant wave height, scientifically represented as Hs or Hsig, is one important level when
considering the statistical distribution of ocean waves. The most common waves are less than
that of Hs. This implies that encountering the significant wave is not frequent. However,
statistically, when two significant waves come into phase, it is possible to encounter a wave
that is much larger than the significant wave.

Generally, it is assumed that individual wave heights can be described using a Rayleigh Distribution.
For example, given that Hs = 10 meters, or 33 feet, statistically:
• 1 in 10 will be larger than 10.7 m (36 ft)
• 1 in 100 will be larger than 15.1 m (51 ft)
• 1 in 1000 will be larger than 18.6 m (62 ft)

This implies that one might encounter a wave that is roughly double the significant wave height.
However, in rapidly changing conditions, the disparity between the significant wave height and the
largest individual waves might be even larger.