There are several types of ocean currents. Among them there are those that are directed perpendicular to the shore. A rebounding flow is formed during low tide, when water in some areas leaves at different speeds. This phenomenon is not universal, but everyone can face it.
Breaking current
This process may pose a threat to people at sea. Fear is worth shallow reservoirs with a shallow shore, framed by sand spits and skeletons. Natural obstacles do not allow water to smoothly leave the coast.
The fluid pressure on the narrow passage that connects the estuary to the ocean is rapidly increasing. As a result, a rapid forms, along which the water mass rushes off the coast at a speed of up to 3 meters per second. On the surface of the water, the fencing current resembles a stormy river.
How to recognize
- A jet of water directed away from the shore.
- Near the coastal zone the color of the water surface changes. For example, in the middle of the blue sea is a white patch.
- Foam, algae, air bubbles or the like moves in the form of a jet perpendicular to the coastline.
- Gaps in tidal waves reaching a width of 5 to 10 m.
Every fifth fencing current in the ocean gives itself out as one of the listed signs. In other cases, it is almost impossible to recognize a spontaneous “rip”. Rescue professionals will cope with this task, but ordinary tourists cannot do it. Swimmers learn about the existence of a problem only after being pulled into a powerful invisible stream.
How to protect yourself
The fencing current is the most dangerous among such phenomena. Once in the stream, beginners swimmers try to overcome it, and move towards the shore. They quickly run out of energy, while the water continues to carry them further into the sea.
The fencing current in the Black Sea has a small extent. The highest flow rate is observed at the surface, so all objects are not drawn into the water, but are kept afloat. After getting into the stream, rescuers recommend not to resist, but to wait for the moment when the flow rate will weaken. After that, swim a short distance along the coast and move towards the land directly or at an angle. It is not recommended to swim between braids and islands that enclose estuaries.
Coastal currents
Waves directed at an angle to the coastline contribute to the formation of coastal and lateral currents. Their speed is usually not higher than one node, but it all depends on the direction and height of the waves in each case.
The strength of such a current is maximum in the surf zone, it is enough to take the swimmer to dangerous rocks or just to an uncomfortable place. Coastal streams of water can do at the bottom of the recess.
A discontinuous flow is observed when masses of water leave the sea. Big waves approaching the shore form surges that raise the water level. This flow has a length of 30 to 1000 m. The strongest discontinuous flow is observed when there are no waves.
With an increase in the width of the surf line, the force of water movement from the coast increases. Bursting currents cause most accidents when divers dive. This type of water flow is divided into:
- Long lasting, existing over a certain period of time. Most often, from a couple of hours to two months. They arise as a result of changes in the relief of the seabed near the coast.
- Permanent, appearing in the presence of incessant conditions (an opening in the rocks, a funnel or trough).
- Instant, arising spontaneously and just as quickly disappearing.
- Mobile, moving along the coast. Their appearance can be predicted.
Wind currents appear under the influence of powerful air currents above the surface layer of water. The farther inland from the surface, the lower their intensity. In addition to wind, the speed and duration of the current are influenced by water temperature, depth and bottom topography.
Convection currents near the coast are caused by air currents in the direction of the sea. Warm water, heated by the sun, leaves the shallow water. It is replaced by the cold from the depths.
About the ebbs and flows
Ebbs and flows - sea level changes caused by the mutual attraction of the sun and moon. The movement of these phenomena occurs from east to west. The height depends on many factors, including the depth and characteristics of the coastline. The largest fluctuations are observed in narrow bays.
Records for the difference in water level: Penzhinsky bays (11 m) and Fundy (16 m). Full and low water - the name of the highest and lowest points of the level. The magnitude of the tide is the difference between these extremes.
