What factors determine the height of a wave and the sea level variation due to tides?
Breaking waves on a beach are a result of a water parcel approaching shallow water. In most oceans there is almost always some kind of wave motion in the water, depending on currents, the local topography and mainly the winds. So, the bottom of a wave approaching shallow water is slowed down due to frictional forces with the sea floor and the top part all of a sudden moves faster than the bottom part, the wave rolls over, it breaks. The height of the breaking waves what we know as surf is strongly dependent on the geography and on the weather and places along the Pacific coast like California or Hawaii are known for the good surf in winter. Away from the beaches, the height of the wave is an important factor for navigation, ranging from recreational small boats limited to quiet waters to super tankers that can navigate under any condition. In the open ocean, tsunamis are not dangerous because the wave length is so long that ships do not feel them. Tsunamis only get dangerous when they
