Basic knowledge for self-rescue in flood and water disaster prevention

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This post was last edited by yinkuilin6868 on 2016-6-15 08:31. I. Basic Knowledge of Flood Control 1. What is flood control? Flood control refers to the various efforts carried out to prevent and mitigate flood disasters, including flood forecasting, flood control scheduling, and the utilization of flood control infrastructure. The term \"flood\" refers to the seasonal or periodic rise in water levels in waters such as rivers and lakes. 2 Characteristics of rainfall: Based on the reasons for air ascent, rainfall can be classified into four types: orographic rain, topographic rain, convective rain, and typhonic rain. 24-hour rainfall intensity and category (unit: millimeters): light rain 10, moderate rain 10-25, heavy rain 25-50, torrential rain 50-100, extremely heavy rain 100-250, and super-typhonic rain greater than 250. II. Floods: How to Prepare and Save Yourself During a Flood (1) Based on flood information provided by television, radio, etc., as well as the location and structure of your dwelling, calmly choose a place to evacuate to. Avoid the situation where the water arrives before the person does. (2) Identify the road signs to determine the evacuation route and destination, so as to avoid taking the wrong path due to panic. (3) Stock up on instant foods or enough food to last for a few days, and prepare sufficient drinking water and daily necessities. People who fail to evacuate in time when a flood occurs should quickly move to nearby slopes, upper floors of sturdy buildings, high ground, or similar locations. (4) In mud-brick houses, if people are unable to evacuate in time when a flood arrives, they should quickly gather floating materials such as door panels, tables and chairs, wooden beds, and large pieces of foam plastic to make rafts for escape. Swimming and climbing onto rooftops are not advisable. (5) Before a flood occurs, waterproofly pack valuable items that are difficult to carry and bury them underground. (6) If surrounded by floods, try to get in touch with the local ** or authorities as soon as possible. Report your location and the danger situation, and actively seek rescue. (7) Under no circumstances should one try to swim to escape; one must not climb electrified poles or towers, and should stay away from tilted poles and broken wires. (8) If caught in a flood, be sure to hold on to anything fixed or floating as much as possible to look for an opportunity to escape. III. Debris Flows
1. What are debris flows? Debris flows refer to small-scale floods in mountainous areas that are characterized by high flow velocity, a short duration, and often contain large amounts of sediment and rocks. They occur suddenly and have great destructive power. 2 What to do in case of sudden flash floods (1) It is essential to stay calm, quickly assess the environment around you, and flee to the mountains or higher areas as soon as possible. If it is not possible to escape immediately, find a relatively safe place to take shelter from the flood. (2) When a flash flood occurs, never run in the direction of the flood flow; instead, move quickly to the sides to take cover. Do not cross the river by wading lightly. (3) Under no circumstances should the timing of fleeing floods be delayed in order to move poultry, valuables, or for other reasons, resulting in the loss of both lives and property. (4) If trapped in the mountains due to flash floods, one should promptly contact local ** or authorities to seek rescue. 3. What should students in mountainous areas do when flash floods occur? If heavy rain falls in mountainous areas, flash floods can occur within half an hour. Flash floods come swiftly, with high flow rates and strong erosive power; they are highly destructive and can cause severe disasters in mountainous areas. (1) Flash floods may occur; teachers must accompany students when crossing rivers. When the water is deeper than the knees, a single person should not cross the river; when the water reaches waist height, no one should cross it either. In the event of being swept away by the current, one must stay calm and try to grab onto floating objects in the river or tree roots and branches on the bank in order to survive. (2) When the flood rises rapidly and the teacher is unable to escort them across the river, all students should return to school to spend the night there. (3) During the summer vacation, when mowing grass or plowing on the mountains and encountering heavy downpours, one must take precautions against landslides, falling rocks, and collapses when taking shelter in caves or similar places. (4) During thunderstorms, the water levels in river valleys rise rapidly; students should move to higher ground, but they should not stay under large trees nor go to the tops of hills to avoid being struck by lightning. (5) If wires are hanging low, do not touch them with your hands or body; if the hanging wires have been washed by river water, do not stay near the riverbank, and certainly do not try to cross the river there. All of these situations can lead to electric shock accidents, posing a threat to life safety. (6) When the water depth is less than one meter and the fluctuations in water level are not significant, and elementary school students need to cross the river urgently, the teacher can organize them and take the following measures: use long ropes or backpack straps or water bottle straps to tie around each person’s waist, have them line up in a row, keep their hands tightly connected to one another, and cross the river at an angle in the direction of the current to reduce resistance from the water. 4. What to do if roads are blocked on the way to or from school? (1) In cases where floods have washed away roads, caused them to collapse, or severed them in half with rapid currents flowing through, one must “take temporary shelter” in a safe place; under no circumstances should one attempt to cross such roads. (2) When mountain roads are blocked by debris from landslides, it is safer to take a detour uphill and pass through the upper part of the landslide area. (3) When floods destroy bridges and culverts, and the river current is strong with the bridge deck still collapsing, it is absolutely forbidden to attempt to cross by force, as it can be fatal. (4) When a high-voltage tower collapses and power lines hang across the road, one must keep a distance from them to prevent electric shock ； Second, it is necessary to report to the relevant departments for prompt repair. At this moment, there is no room for luck to get by. IV. Typhoons 1. What is a typhoon? The typhoons we are referring to are vortexes of warm and humid air that form over the tropical seas of the western Pacific Ocean; they are essentially tropical cyclones. It is often accompanied by strong winds, heavy rain, and storm surges. 2 Measures for preventing typhoons (1) Based on the potential impacts of typhoons, meteorological agencies use three types of announcements—”notifications,” “alerts,” and “emergency alerts”—to inform the public through forecasts ； Meanwhile, depending on the potential impact of a typhoon, four types of typhoon warning signals—blue, yellow, orange, and red—are issued to the public, ranging from mild to severe. The public should pay close attention to media reports on typhoons and take preventive measures in a timely manner. (2) Before a typhoon arrives, it is necessary to prepare flashlights, radios, food and drinking water, as well as common medicines, for emergency use. (3) Close the doors and windows, check whether they are secure, remove any hanging items, and verify that the electrical wiring, gas supply, and heating equipment are safe. (4) Move animals and other items kept outdoors inside, especially items on the roof and flower pots outside windows must be brought indoors; anything that is prone to being blown around outdoors should be secured properly. (5) Do not travel, swim, or boat in areas affected by typhoons. (6) Outdoor billboards, temporary shacks, temporary buildings, and construction scaffolding should be reinforced; street trees and drainage systems in urban areas need to be temporarily strengthened and cleaned. (7) People living in low-lying areas and dilapidated houses in urban and rural areas should be evacuated promptly. (8) The heavy rains brought about by typhoons can easily trigger disasters such as floods, landslides, and mudslides; relevant schools, industrial and mining enterprises, as well as roads located near mountains should take enhanced preventive measures. If necessary, measures such as suspending school operations, shutting down factories, and sealing off roads should be taken. (9) When a typhoon is approaching, walking along rivers and streams is prohibited. V. Debris Flows 1. What is a debris flow? A debris flow is a special type of flood that occurs in mountain valleys or slopes, triggered by heavy rainfall or the melting of snow and ice, and it contains large amounts of sediment, stones, and boulders. Debris flows often occur alongside flash floods; they are characterized by their fierce momentum, sudden onset, and high destructive power. In a very short time, vast amounts of debris flow uncontrollably out of the ravines and accumulate at their mouths. For example, on June 10, 2005, a sudden downpour occurred in Ning’an City, Heilongjiang Province, instantly giving rise to a flood peak and triggering a mudslide disaster. The hardest-hit was the Central Primary School in Shalan Town of that city; 351 students were in class at the time, and 88 of them died due to the collapse of the classrooms. 2. How to stay safe during a mudslide: (1) When people are active in valleys, in the event of heavy or torrential rain, they must quickly move to safe highlands. They should not take shelter or remain in low-lying valley bottoms or at the base of steep slopes. (2) Pay attention to your surroundings, and be especially vigilant to any unusual sounds coming from afar, such as the sound of rockfalls or roaring floods, as these may be signs of an impending mudslide. (3) When a mudslide is approaching, run immediately to higher ground on both sides of the gully; never run upstream or downstream along the direction of the gully. (4) After the heavy rain stops, do not rush back to your dwelling in the gully; wait for some time. VI. Landslides and collapses 1 A landslide refers to the phenomenon in which rock and soil masses on a slope, affected by factors such as river erosion, groundwater activity, earthquakes, and human-induced slope cutting, slide down the slope as a whole or in fragments along certain weak surfaces under the force of gravity. Commonly known as “walking the mountains”. 2 Precursors of landslides (1) Before a major landslide occurs, springs that have been dry for many years may \"come back to life,\" and abnormal phenomena such as the sudden drying up of springs and wells along with sudden changes in water levels may also occur. (2) The appearance of transverse and longitudinal radial cracks in the middle or front part of the landslide body indicates that the landslide body has entered a state on the verge of sliding. (3) Before the major landslide, uplift (protrusion) occurred in the soil at the foot of the slope front of the landslide mass. (4) The cracks at the rear edge of the landslide mass expand rapidly, with hot air or cold wind escaping from them. (5) Animals are extremely panicked, and plants are deformed. This can result in domestic animals such as pigs, dogs, and cows becoming anxious and unable to sleep, rats running around instead of returning to their holes, and trees withering or bending. (6) Before a major landslide, the horizontal and vertical displacements observed over a long period on the landslide mass show an accelerating trend, which is an obvious sign of an impending landslide. After the precursors of these landslides occur, preventive measures must be taken immediately. 3 Collapse refers to the geological phenomenon in which rock and soil masses on steep slopes suddenly break away from their parent material under the force of gravity, roll down, and eventually accumulate at the foot of the slope or in valleys. 4 What to do in case of landslides or collapses (1) Pedestrians and vehicles should not enter or pass through areas marked with warning signs indicating a risk of landslides or collapses. (2) When signs of a landslide or collapse are detected, they should be immediately reported to local ** or relevant authorities. At the same time, other affected residents should be notified so that they can prepare for evacuation. (3) When you are on a landslide area and feel the ground moving, flee as quickly as possible to stable areas on either side. Under no circumstances run upward or downward from the landslide area. (4) When you are trapped inside a landslide and unable to escape, find an open area with a gentle slope to take shelter in, but stay away from houses, walls, utility poles, and similar structures. (5) When you are at the front of a landslide mass or below a collapse zone, your only option is to flee quickly to either side. VII. What is lightning? Lightning is a discharge phenomenon in the atmosphere. During the formation of thunderstorm clouds, one part accumulates positive charge while another part accumulates negative charge. When these charges build up to a certain level, discharge occurs. Discharges occur either between clouds or between clouds and the ground; these two types of discharges are commonly referred to as thunder. The damage caused by lightning is also known as a lightning strike. Lightning strikes can be divided into direct strikes and indirect strikes. Lightning strikes can occur throughout the year, while severe lightning is more common at the transition between spring and summer and during summer. 2 How to prevent lightning strikes: Methods of taking shelter indoors (1) During thunderstorm weather, make sure to close doors and windows to prevent side flashes and ball lightning from entering. (2) During thunderstorms, it is best to turn off the power supply of household appliances and unplug them ； Do not use radios and televisions with external antennas ； Do not answer or make landline calls. (3) During thunderstorms, do not touch antennas, gas pipes, wire fences, metal windows, building exteriors, etc ； Stay away from energized equipment ； Do not stand barefoot on mud or concrete. (4) Do not take a shower with a spray head during thunderstorms. Outdoor lightning protection methods: (1) Immediately find a place to take shelter; you can choose buildings equipped with lightning rods, steel frames, or reinforced concrete, but be careful not to get too close to any part of the lightning protection system. If no shelter can be found, one can crouch down, keep the feet together, wrap the arms around the knees, and try to lower the body’s center of gravity as much as possible to reduce the area of contact between the body and the ground. Wearing a waterproof raincoat immediately will provide better lightning protection. (2) Do not stay in outdoor swimming pools, open waters, or small boats ； Don’t stay at the edge of the woods ； Do not stay near objects such as utility poles, flagpoles, hay stacks, tents, and other structures that lack lightning protection devices ； Do not stay near exposed metal objects such as railway tracks, water pipes, gas pipes, electrical equipment, tractors, motorcycles, etc ； Do not stay on high places such as mountaintops or rooftops ； Do not approach isolated large trees or chimneys ； Do not hide in solitary shacks or watchtowers in the abandoned mining areas. (3) It is not advisable to use an umbrella in the open fields, or to hold badminton rackets, golf clubs, hoes, etc. high in the air ； Outdoor activities such as playing golf, soccer, climbing, fishing, and swimming should be stopped immediately. (4) Avoid riding motorcycles or bicycles, and under no circumstances ride them at high speed during thunderstorms ； When in a car, make sure to close the doors and windows properly. (5) When a high-voltage line is struck by lightning and falls to the ground, people in the vicinity should remain highly vigilant and be careful of electric shock caused by the \"step voltage\" on the ground. The correct way to escape is to keep your feet together and jump away from the dangerous area. (6) When multiple people are in the wild together, they should keep a distance of several meters from each other and not crowd together. (7) It is advisable to turn off your phone when in an open area. VIII. How to take preventive measures during heavy rainstorms (1) When heavy rain is approaching, close the doors and windows to prevent rainwater from entering the house; once water gets in, immediately turn off devices such as electricity and gas supplies. (2) Cut off dangerous outdoor power supplies in low-lying areas. (3) Do not use underground passages or passages under viaducts. (4) Do not walk in flowing water; water as deep as 15 centimeters can cause a person to fall. (5) In mountainous areas, if the water flow is rapid, turbid, and contains sediment, it may be a precursor to a flash flood; one should leave the stream or riverbed. (6) When driving in heavy rain, turn on the fog lights, drive slowly, be vigilant against flash floods, and avoid areas with water accumulation and landslides. (7) Be aware of electrical facilities on the street; if wires fall, stay away immediately and report it to the electricity authorities right away. (8) If severe flooding is likely in the residence, evacuate and take shelter in a safe place. (9) In case of danger, please call 110 for help. There has been plenty of rain recently. To better prevent flooding, avoid disasters, and create a safe and harmonious environment is the common desire of everyone. Rain in nature comes in various forms: there is the gray, light drizzle, the continuous downpours, and also the intense thunderstorms. In a given area, if heavy rain falls in a short period of time, river levels rise very quickly, which can easily cause them to overflow their banks. This leads to flooding of farmlands and villages, as well as damage to roads and houses, leaving many people without a home. This is the flood disaster caused by the heavy rain. What is a heavy downpour? A heavy downpour refers to rain with an extremely high precipitation volume. So how is the amount of rainfall measured? Meteorological officers place a metal cylinder with a diameter of 20 centimeters in an open area at the ground-based observation station – this cylinder is known as a rain gauge. The amount of rain it collects over 24 hours constitutes the daily rainfall, which can be measured using a measuring cup. The Central Meteorological Agency defines light rain as rainfall of less than 10 millimeters per day, moderate rain as 10–25 millimeters, heavy rain as 25–50 millimeters, and torrential rain as more than 50 millimeters. Severe rainstorms pose certain risks, but they are not terrifying. As long as all necessary precautions are taken, no danger will occur. Knowledge for Self-Rescue in Flood and Rainstorm Prevention I. Before the occurrence of heavy rains and floods, residents living outside urban areas should avoid building houses in low-lying areas or regions prone to landslides, as well as in places that may be flooded by water overflowing from rivers. Do not artificially occupy the natural flood discharge cross-section of the river channel. At the beginning of each summer, it is necessary to inspect the area in front of and behind the house, paying attention to any changes in the nearby mountains and looking for signs of cracks or landslides. Urban residents, shopping malls, schools, factories, and enterprises should be familiar with their surrounding environment and equip themselves with necessary waterproofing and drainage facilities, such as canvas, woven bags, sand and gravel, wooden planks, and water pumps. Pay attention to the forecasts issued by the local meteorological and flood control authorities. In crowded areas such as shopping malls, schools, and squares, it is necessary to promptly carry out tasks such as guiding and evacuating people. II. After heavy rainstorms and floods occur, if any significant signs are detected or disasters have already taken place, the information must be disseminated as quickly as possible to draw **attention, thereby striving to control the progression of the disaster and facilitate rescue efforts. In an emergency, stay calm, act quickly, and make a decisive decision to give up. Rainstorm floods are characterized by sudden onset, rapid rises and falls, and a short duration. When an increase in water level in the river is detected, evacuate immediately; do not be careless or hesitate. During the flood season when rivers rise, never try to cross them forcefully; instead, wait patiently until the water levels drop, or take a longer route to cross. During heavy rain and floods, pedestrians should stay away from dangerous areas such as high-voltage lines and electrical equipment to take shelter from the rain, and they should turn off their mobile phones during thunderstorms. The school should decide whether to suspend classes temporarily or keep students on campus to avoid floods, arrange temporary accommodation and meals, and inform the parents so as to prevent accidents from occurring while they try to find their children. Immediate first aid measures such as artificial respiration should be carried out for the drowning person. III. How to seek help when trapped by water: Whether alone or with a group of people, if caught in a flood and trapped on a solidly built high ground or in a brick-concrete residential building, one can simply hold their position in an organized manner and wait for rescue, or wait until the flood levels drop after they rise sharply. If trapped by floods in low-lying areas, in houses made of adobe or wood, and the situation is critical (landslides are treated separately), those with access to communication means can use them to report the flood situation and their predicament to the local authorities and flood control departments in order to seek assistance ； In areas without communication facilities, fireworks can be set off, brightly colored clothes can be waved back and forth, or everyone can shout for help together, in order to send out emergency signals to the outside world and seek rescue as soon as possible ； At the same time, look for larger floating objects and take proactive self-rescue measures. IV. How to rescue people trapped by floods: Floods develop rapidly, have strong impact forces, and pose a high level of danger; therefore, it is essential to act swiftly to rescue those trapped by them. Any citizen of society, upon receiving a distress signal from someone who is in trouble, should first convey that distress message as quickly and efficiently as possible, inform the local authorities and nearby residents, and immediately get involved in the rescue efforts ； Upon receiving the alarm, local ** and grassroots organizations should, as quickly as possible, organize rescue teams to rush to the scene and make full use of various rescue methods to save those trapped ； During the operation, it is also necessary to continuously work on stabilizing the emotions of those who are trapped, in order to prevent new accidents from occurring ； Special attention must be paid to preventing anyone from falling back into the water during the rescue and transfer process, to ensure that all people are safely rescued ； It is also necessary to carefully arrange for the temporary living needs of those who have been rescued, as well as to provide medical care and other forms of support.