Wave Energy Wave Energy Wave height offshore as shown by the wave buoys and in the Oceanweather images does not equate directly into surf height at the break. What is important is the combination of the wave period and wave height.
Period is directly related to the speed the wave is travelling.
The longer the period the faster the wave and the more energy in contains. The shallower the water the slower they travel. The total energy in the waves has not changed so when the speed is decreased the height increases, the waves get bigger and steeper. However, some energy is lost through friction with the sea bed, causing the wave height to decease. This is particularly significant where there is a large continental shelf.