A tourist drowned while swimming in Hainan, probably because he encountered this "invisible killer" on the beach!

Recently, a female netizen posted a message online asking for help, hoping that netizens could help find someone or provide clues. She said in the message that on July 2, she and her boyfriend came to Haikou to watch Jay Chou's concert. At around 6 pm on July 4, her boyfriend disappeared while playing in the water at the beach. Based on the clues provided by a friend surfing nearby, the message immediately attracted the attention of many netizens, who forwarded it to help find someone.

On July 9, relevant personnel from the Third Detachment of the Coast Guard Corps of the Public Security Department of Hainan Province confirmed to reporters that they did receive a police report some time ago, and the man was later found but unfortunately died. The tourist who was found was from Sichuan, and the forensic doctor determined that he drowned. Merchants near the beach where the incident occurred said that the man went to the sea alone and did not buy any surfing items.

Although it is not certain whether the man encountered the rip current situation reported online, the incident has also triggered popular science about rip currents on the Internet. The weather is hot, so beware of the "invisible killer" when going to the beach to play in the water and cool off↓↓

Hidden and dangerous rip currents

In fact, rip currents are not a "new thing". As early as August 2017, my country's first batch of rip current warning signs were erected in key coastal tourist areas in Sanya and Lingshui, Hainan.

Rip current, scientifically known as rip current, is a strip-shaped surface current that flows back into the sea through the breakers after the waves break under the radiation stress and pressure difference of the waves on the sea surface. The flow rate is mostly 0.3-1 m/s, and the fastest can reach 3 m/s. Its length can be 30-100 meters or even longer, and the flow direction is almost perpendicular to the coastline.

Zhang Yao, assistant researcher at the Marine Disaster Reduction Center of the State Oceanic Administration, said that rip currents can quickly carry floating objects or swimmers to deep waters, and even very good swimmers and the fastest swimmers in the world cannot escape their killer.

According to the official Weibo account of People's Daily, research in Brazil and Australia shows that about 90% of drownings at the seaside are caused by rip currents. It is understood that the flow rate of a typical rip current is about 2 meters per second, which is faster than the average person's swimming speed. Even lifeguards are often pulled out to sea by it during training.

Rip currents are easier to identify from the high ground near the shore. Zhang Yao said that they are mainly calm waters with white waves parallel to the shoreline. If you see such a phenomenon, you must be careful. In addition, rip currents are more likely to occur at low tide; the shoreline or structures protruding to the sea, such as seawalls and reefs, are high-risk areas for rip currents.

Regular bathing places are safer

In the hot summer, many people choose to swim at the beach. In fact, the ocean is the water body with the most complex water conditions. Not only is the sea water deep, but there are also aggressive marine life. At the same time, the wind and waves are the strongest, the ocean currents are the most complex, and the reefs are even more dangerous. The famous movie "Jaws" is based on such a story.

In addition, the ultraviolet rays at the seaside are strong, and there are natural creatures such as jellyfish near the coastline, which can easily cause unnecessary damage to human health. Once you fall into the sea and get into trouble without effective rescue, the chance of survival is low. Even mature commercial beaches have the risk of being swept away or knocked unconscious by the waves. Even the most experienced swimmers cannot take the marine environment lightly.

When you encounter a rip current, you must not swim against the current toward the shore, as this will only accelerate your physical exhaustion. The correct approach is to swim perpendicular to the current and along the coast. Alternatively, you can go with the flow, wait until you reach the end of the rip current, then swim along the coast for a while, and finally swim back to the shore.

On the other hand, "being able to swim" and "being able to swim in open water" are two completely different concepts, because the technical levels and swimming techniques of the two are completely different. In addition to improving physical skills, swimming in open waters also requires excellent swimming equipment and psychological qualities. For large open waters such as the sea, Professor Wen Yuhong, Dean of the School of Swimming at Beijing Sports University, believes that for the general public, it is necessary to choose a regular beach, otherwise it is difficult to talk about safety issues.

Other water body considerations

01 Swimming Pool

Safety officers are not "all-purpose saviors". Observe the water conditions before entering the water.

Key Features:

1. The water depth is limited, and most swimming pools are equipped with lifeguards, which has a high safety factor and is suitable for beginners.

2. Swimming pools with different conditions vary greatly, and most of them have stagnant water and average sanitary conditions. Some swimming pools add disinfectants and other substances to the water, which can easily cause harm to swimmers.

3. Children have a higher rate of drowning in swimming pools than adults.

Note:

When swimming in a pool, you must observe the water conditions before entering the water. Under normal circumstances, the water in a swimming pool should be blue and transparent. If the water in a swimming pool is turbid, it means that the water in the swimming pool is not very sanitary. If there is a pungent smell in the swimming pool, it means that the chlorine and ammonia content in the water is too high, which will irritate and damage the human skin.

The water in the swimming pool is from shallow to deep. Beginners can start from the shallow water area, or choose to swim only in the shallow water area. For those who have mastered the skills, they must also do warm-up exercises before entering the water, get on the shore and straighten themselves if they have cramps, and ask for help immediately if there is any accident. On the other hand, although there are lifeguards in the swimming pool, they are not omnipotent saviors, because the area of ​​the swimming pool is usually very large, and sometimes even if you are drowning, the lifeguard may not be able to find it immediately, so it is best to swim with friends, or make sure to swim within the sight of the lifeguard, and don't stay too long in some blind spots.

02 Lake

The water temperature is inconsistent between the upper and lower parts, and artificial lakes are safer

Key Features:

1. The water surface is calm, with few whirlpools and undercurrents, suitable for general wild swimming enthusiasts.

2. There are two types: natural lakes and artificial lakes (reservoirs). The latter are safer than the former, but there are certain restrictions on swimming.

3. Fish ponds, water ponds, etc. are not considered lakes.

Note:

Compared to rivers, lakes are relatively calm, but compared to swimming pools, lake water is relatively more fluid. Swimming in a lake is considered entering open waters, so you should be especially careful about your physical condition before entering the water. After entering the water, you should be aware of the direction and judge the distance to avoid getting lost or running out of energy.

Lakes are generally deep, and the underwater temperature remains stable all year round, but the surface water temperature is often related to the weather. Swimmers who encounter cold water in the lower layer are prone to calf cramps. In addition, many reservoir dams are sloped, and there is a cliff-like deep water area just one or two steps away. Some swimmers did not estimate the water depth well, resulting in the embarrassing situation of "not being able to get out". In addition, reservoirs also function as energy storage power stations, and the water level changes greatly during the day. Do not swim in such reservoirs.

03 River

The water body is complex and dangerous, so go upstream and pay attention to changes upstream and downstream

Key Features:

1. Water flow is greatly affected by seasonal and climatic factors.

2. The water conditions are complex, and whirlpools, turbulence, reefs, etc. are very common.

3. The shallower the river and the narrower the water surface, the faster the water flow; on the contrary, in relatively open areas, the water flow is relatively slow.

Note:

Compared with lakes and swimming pools, swimming in rivers is much more dangerous. Different lakes and reservoirs have common water conditions, but every section of every river, every season of every section of the river, and every moment of every season are unique! Especially in the south, when the flood season comes, the flood conditions are complicated. The flow speed of many rivers is faster than the swimming speed of people. It is impossible to really "swim" in it. You can only drift along the water. There are even cases of drowning upstream and the body is found downstream.

If you really want to swim in a river, it is recommended to swim upstream, so that you can control the rhythm and speed, and avoid the situation of going downstream and not being able to return. At the same time, before swimming, you must understand the weather and climate trends, understand the relevant conditions of the upstream and downstream areas of the river, and make sure there are no reservoirs or other areas upstream that are easy to open the gates to release water. You must also determine the weather conditions upstream to ensure that there is no heavy rainfall, because this is very likely to cause rapid changes in the water flow; in addition, pay attention to whether there are obstacles such as waterfalls and dams downstream, and find a good landing point in advance.

Source: WeChat official account of "Beijing Science and Technology News Agency" (compiled from Nanfang Daily, Red Star News, Beijing Science and Technology News)