What do you know about natural disasters?
What Are Natural Disasters?
Natural disasters are extreme, sudden events caused by environmental factors that injure people and damage property. Earthquakes, windstorms, floods, and diseases all strike anywhere on earth, often without warning.
Natural disasters such as flood, fire, tornado, earthquake, tsunamis are becoming more and more frequent on our planet. In short description a natural disaster is a result of a natural hazard, which has a negative effect on human beings. These geologic processes can lead to serious consequences such as loss of life, property damage, economic problems.
Certain areas are more exposed to natural disasters. For example, most of New Zealand’s coastline is exposed to tsunami hazard, while the Far East region is exposed to floods. Being aware of possible dangers, people should be prepared to protect themselves, their families and communities. Two important preparation steps are the developing of emergency plan and assembling a supply kit.
However, all the known disasters have unique nature and should be approached separately.
Avalanches are masses of snow, ice, and rocks that fall rapidly down a mountainside. They can be deadly. Avalanches come in many shapes and sizes. Avalanches are most common during the winter, December to April in the Northern Hemisphere, but they do occur year-round. Learning about avalanches really helps people decide when and where, and how to recreate.
A landslide is defined as the movement of a mass of rock, debris, or earth down a slope due to gravity. The materials may move by falling, toppling, sliding, spreading, or flowing. Landslides can be triggered by rainfall, snowmelt, changes in water level, stream erosion, changes in ground water, earthquakes, volcanic activity, disturbance by human activities, or any combination of these factors. Earthquake shaking and other factors can also induce landslides underwater. These landslides are called submarine landslides. Submarine landslides sometimes cause tsunamis that damage coastal areas.
An earthquake is the result of a sudden collision among the tectonic plates of the Earth. Such collision leads to massive and occasionally deathly vibrations.
An earthquake is the shaking of the surface of the Earth resulting from a sudden release of energy in the Earth’s lithosphere that creates seismic waves. Earthquakes can range in size from those that are so weak that they cannot be felt to those violent enough to propel objects (and people) into the air, and wreak destruction across entire cities. The seismicity, or seismic activity, of an area is the frequency, type, and size of earthquakes experienced over a period of time.
Sinkholes are caused by erosion. They may appear suddenly and have devastating consequences. Sinkholes have both natural and human causes. Land made of a soft underground rock layer is often riddled with sinkholes, since the rock layer is easily dissolved. Roads, buildings, and other types of construction may cause water to collect in certain areas and wash away the supporting rock layer (especially at low sea levels and after a heavy rainfall).
Volcanoes are Earth’s geologic architects. They’ve created more than 80 % of our planet’s surface,There are volcanoes on every continent, even Antarctica. Some 1,500 volcanoes are still considered potentially active around the world today.
The most common type of volcanic eruption occurs when magma (the term for lava when it is below the Earth’s surface) is released from a volcanic vent. Eruptions can be effusive, where lava flows like a thick, sticky liquid, or explosive, where fragmented lava explodes out of a vent.
The deadliest eruption in recorded history was the 1815 explosion of Mount Tabora in Indonesia. The blast was one of the most powerful ever documented and created a caldera — essentially a crater — 4 miles across and more than 3,600 feet deep. A superheated plume of hot ash and gas shot 28 miles into the sky, producing numerous pyroclastic flows when it collapsed.
The eruption and its immediate dangers killed around 10,000 people. But that wasn’t its only impact. The volcanic ash and gas injected into the atmosphere obscured the sun and increased the reflectivity of Earth, cooling its surface and causing what’s known as the year without a summer. Starvation and disease during this time killed some 82,000 more people, and the gloomy conditions are often credited as the inspiration for gothic horror tales, such as Mary Shelley’s Frankenstein.
A flood is an overflow of water that submerges land. In severe cases it can result in human and animal deaths. Very often the crops are destroyed, which brings famine.
A tsunami is a series of ocean waves that sends surges of water, sometimes reaching heights of over 100 feet (30.5 meters), onto land. These walls of water can cause widespread destruction when they crash ashore. These waves are typically caused by large, undersea earthquakes at tectonic plate boundaries.
Most tsunamis–about 80 percent–happen within the Pacific Ocean’s “Ring of Fire,” a geologically active area where tectonic shifts make volcanoes and earthquakes common. Tsunamis may also be caused by underwater landslides or volcanic eruptions.
Tsunamis race across the sea at up to 500 miles (805 kilometers) an hour—about as fast as a jet airplane.
The best defense against any tsunami is early warning that allows people to seek higher ground.
A limnic eruption, also known as a lake overturn, is a rare type of natural disaster in which dissolved carbon dioxide (CO2) suddenly erupts from deep lake waters, forming a gas cloud capable of suffocating wildlife, livestock, and humans. Scientists believe earthquakes, volcanic activity, and other explosive events can serve as triggers for limnic eruptions. Lakes in which such activity occurs are referred to as limnically active lakes or exploding lakes.
A cyclonic storm is a storm system in which the air rotates cyclonicaly. In the Northern Hemisphere, that is counter-clockwise. In the Southern Hemisphere, that is clockwise. Examples of cyclonic storms: dust devils, supercell thunderstorms, tornadoes, tropical cyclones, extratropical cyclones.
In the Atlantic and the northeastern Pacific oceans, a tropical cyclone is generally referred to as a hurricane (from the name of the ancient Central American deity of wind, Huracan), in the Indian and south Pacific oceans it is called a cyclone, and in the northwestern Pacific it is called a typhoon.
The term blizzard describes a severe winter weather condition (violent snowstorm) characterized by strong winds, cold temperatures, and reduced visibility due to falling or blowing snow.
A hailstorm is an unusual weather phenomenon in which balls of ice, called hail, fall from the sky. The ice balls are nothing more than solid precipitation that will form under certain conditions. Hail is formed at high altitudes within massive clouds when supercooled water droplets adhere to each other and form layers of ice.
Ice storms are caused by freezing rain. The raindrops move into a thin layer of below-freezing air right near the surface of the earth, allowing them to freeze on contact to the ground, trees, cars and other bjects. Ice accumulates when super-cold rain freezes on contact with surfaces that are below freezing point.
A cold wave (known in some regions as a cold snap or cold spell) is a weather phenomenon that is distinguished by a cooling of the air. A cold wave is a rapid fall in temperature within a 24-hour period requiring substantially increased protection to agriculture, industry, commerce, and social activities. The precise criterion for a cold wave is determined by the rate at which the temperature falls, and the minimum to which it falls. This minimum temperature is dependent on the geographical region and time of year.
A heat wave is a period of unusually and excessively hot weather. The worst heat wave in recent history was the European Heat Wave of 2003.
Drought is the unusual dryness of soil caused by levels of rainfall significantly below average over a prolonged period. Hot dry winds, shortage of water, high temperatures and consequent evaporation of moisture from the ground can also contribute to conditions of drought. Droughts result in crop failure and shortages of water.
Thunderstorms are dangerous storms that include lightning. Severe storms, dust clouds, and volcanic eruptions can generate lightning. Apart from the damage typically associated with storms, such as winds, hail, and flooding, the lightning itself can damage buildings, ignite fires and kill by direct contact.
A tornado is a rapidly rotating column of air that is in contact with both the surface of the Earth and a cumulonimbus cloud. Tornadoes occur most frequently in North America (particularly in central and southeastern regions of the United States colloquially known as tornado alley), Southern Africa, northwestern and southeast Europe, western and southeastern Australia, New Zealand, Bangladesh and eastern India, and southeastern South America.
Wildfires are large fires which often start in wildland areas. Common causes include lightning and drought but wildfires may also be started by human negligence or arson. They can spread to populated areas and can thus be a threat to humans and property, as well as wildlife.
I didn’t know that there are so many natural disasters in the world.I am very glad that there are no such terrible natural disasters in our district as tsunami or tornado. We have hailstorms, but they are not so hazardous.