So, Just How Are Wave Heights Measured?

Crest The highest point of a wave.
Trough The lowest point of a wave.
Wave Height The distance from the trough to the crest.
Wave Amplitude The distance from the trough to the point of the undisturbed water surface.  Wave amplitude is always 1/2 wave height.
Wavelength Distance from trough to trough or crest to crest.

What is "Significant Wave Height"

Significant Wave Height is defined as the height of the top third of all waves.  This term is used because experience has shown that trained spotters generally overestimate wave heights.  The National Weather Service forecast of wave heights are defined as "Significant Wave Heights".   


What is Wave Steepness and
Are Great Lakes Waves Steeper Than Ocean Waves ?

Wave Steepness is defined as the Wave Height divided by Length.  Waves on the Great Lakes are generally much steeper that ocean waves because of, among other things,  limited fetch.  Steeper waves are much more difficult to maneuver in.  Therefore, 10 foot waves on the Great Lakes are much more difficult to get around in than those same 10 foot waves on the ocean.  

National Weather Service
Weather Forecast Office Buffalo
587 Aero Drive
Buffalo, N.Y. 14225-1405
(716) 565-0204 or (716) 565-0802

Page last modified: June 13, 2006 at 1:25:00 AM
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