Lifeguards

Waves

Wave size is determined by wind speed, wind duration and the amount of open water over which the wind blows. There are three different types of wind waves: ripples (capillary waves), seas and swells. Ripples appear smooth on the water's surface and die when the wind stops. As the wind picks up speed, ripples grow into larger, more irregular waves called seas. As waves move away from the wind, they begin sorting themselves into groups moving at the same speed and in the same direction. These "orderly" waves are called swells.

A breaking wave is a wave that collapses because its base can no longer support its top. When it runs into shallow water, two wave systems oppose and combine forces or the wind grows strong enough to blow the crest off the base of the wave. There are three main types of breaking waves. Spilling or rolling waves are the safest and can be found in sheltered areas. Plunging or dumping waves break suddenly and push swimmers to the bottom with great force. They can be found where there is a sudden rise in the sea floor. Surging waves may not break as the water below them is very deep. These waves can knock swimmers over and drag them into deeper waters.

Rip currents, powerful, channel currents flowing away from the shore, can occur at any beach with breaking waves. The majority of ocean rescues are due to swimmers struggling in rip currents. Rogue or sleeper waves, very large, unpredictable waves, also cause many drownings, catching swimmers near the shoreline off guard and washing them out to sea.