NATURAL DISASTERS:
Natural disasters, such as hurricanes and flooding, cost money and resources that are needed to move the Commonwealth of The Bahamas forward towards improving the lives of residents, and measuring nation building against the UN 2030 agenda. The latter Sustainable Development Agenda includes 17 specific goals. It recognizes the specific challenges faced by the SIDS such as The Bahamas. Small islands can be particularly vulnerable to the impacts of climate and natural disasters caused by the numerous tropical storms that affect the Bahamas. The 2030 Agenda also encourages all United Nations Member States to “develop as soon as practicable ambitious national responses to the overall implementation of this Agenda.” major natural disasters in India include flood cyclone, droughts earthquake, and Tsunami. apart from this disaster, there are other disasters such as landslides, forest fires, avalanches ,and and cloudburst. India has witnessed a Paradigm shift in natural disaster. before the 1970 drought and famine has had the most service impacts in terms of number of people affected. at present, flood, cyclone, and earthquake account for 98% of the total deaths .it is estimated that 68% of India is prone to droughts, 60% of to earthquakes, 12% of floods ,and 8% to cyclones. overall, 85% of Indian territory faces potential hazards on account of natural disaster.
Levels of Disaster:
The severity or degree of damage can be further divided into three categories:
Small Scale Disasters: Small scale disasters are those that extend from 50 Kms. to 100 Kms. So this kind of disasters does not cause much damage.
Medium-scale disasters: Medium Scale disasters extend from 100 Kms to 500 Kms. These cause more damage than a small scale disaster. Moreover, they can cause greater damage if they occur in colonial states.
Large Scale Disasters: These disasters cover an area of more than 1000 Kms. These cause the most severe damage to the environment. Furthermore, these disasters can even take over a country if the degree is high. For instance, the wiping out of the dinosaurs was because of a large scale natural disaster.
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- VARIOUS NATURAL DISASTER IN INDIA:
■ DROUGHTS: Indian agriculture is heavily dependent on monsoon .monsoon varies from year .some regions, specially where monsoon arrive in the the later part of the rainy season, are the most susceptible to droughts. Severe droughts occur in arid and semi- arid zones once in 8 to 10 years.
In the 1980s, two researchers uncovered more than 150 published definitions of drought which they published in the journal Water International. In an effort to bring some order to measuring drought, the scientists grouped the definitions into four basic categories: meteorological, hydrological, agricultural and socioeconomic. The first three descriptions track drought as a physical phenomenon. The last category deals with drought as a supply-and-demand problem, through the impacts of water shortfalls.
There are four main categories of drought:
Meteorological drought is specific to different regions, depending on the amount of yearly precipitation that’s average for that area. For example, the southwest portion of the United States averages less than 3 inches of precipitation per year, while the Northwest gets more than 150 inches per year, according to the U.S. Department of Interior.
Agricultural drought accounts for the water needs of crops during different growing stages. For instance, not enough moisture at planting time may hinder germination, leading to low plant populations and a reduction in yield.
Hydrological drought refers to persistently low water volumes in streams, rivers and reservoirs. Human activities, such as drawdown of reservoirs, can worsen hydrological droughts. Hydrological drought is often linked with meteorological droughts.
Socioeconomic drought occurs when the demand for water exceeds the supply. Examples of this kind of drought include too much irrigation or when low river flow forces hydroelectric power plant operators to reduce energy production.
■ Floods : floods occur in India because there is a high concentration of rainfall during the monsoon season. Embankments of rivers are not well developed. The flood prone rivers in India are Kosi Damodar and Brahmaputra. Apart from these rivers floods also occur in the West flowing rivers Narmada and Tapti as well as in the Deccan rivers common namely, Mahanandi, Krishna and Kaveri.Floods can also occur in rivers when the flow rate exceeds the capacity of the river channel, particularly at bends or meanders in the waterway. Floods often cause damage to homes and businesses if they are in the natural flood plains of rivers. While riverine flood damage can be eliminated by moving away from rivers and other bodies of water, people have traditionally lived and worked by rivers because the land is usually flat and fertile and because rivers provide easy travel and access to commerce and industry.
Some floods develop slowly, while others can develop in just a few minutes and without visible signs of rain. Additionally, floods can be local, impacting a neighborhood or community, or very large, affecting entire river basins.
■ cyclones : it is a system of winds rotating inward to an area of low pressure, with and anticlockwise. or clockwise circulation. Cyclones are also called depressions. They bring strong winds, rainfall for snowfall. Cyclones may be classified as tropical cyclones and extra –
tropical has temperature cyclones .
Cyclones have also been seen on extraterrestrial planets, such as Mars, Jupiter, and Neptune.Cyclogenesis is the process of cyclone formation and intensification Extratropical cyclones begin as waves in large regions of enhanced mid-latitude temperature contrasts called baroclinic zones. These zones contract and form weather fronts as the cyclonic circulation closes and intensifies. Later in their life cycle, extratropical cyclones occlude as cold air masses undercut the warmer air and become cold core systems. A cyclone’s track is guided over the course of its 2 to 6 day life cycle by the steering flow of the subtropical jet stream.
■ Earthquake : An earthquake is the shaking or vibrating of the earth. An earthquake can range in sizes. As a result, some are so weak that they go unnoticed. But some are so strong that they can even destroy the whole city. Earthquakes can cause disruption of ground. Moreover, the can also cause landslides, avalanches, and Tsunami. However, the center of an earthquake falls mostly offshore.
Causes: These can cause of releasing of the energy. This release is from the core of the earth. Furthermore, the release of energy causes seismic waves. Rupturing of geological faults causes earthquakes. But other events like volcanic eruptions, landslides mine blasts can also cause it.
Types of Earthquake :
Tectonic Earthquake: The Earth’s crust comprises of the slab of rocks of uneven shapes. These slab of rocks are tectonic plates. Furthermore, there is energy stored here. This energy causes tectonic plates to push away from each other or towards each other.
Volcanic Earthquake: This Earthquake is related to volcanic activity. Above all, the magnitude of such Earthquakes is weak. These Earthquakes are of two types. The first type is Volcano-tectonic earthquake. Here tremors occur due to injection or withdrawal of Magma.
Collapse Earthquake: These Earthquakes occur in the caverns and mines. Furthermore, these Earthquakes are of weak magnitude. Undergrounds blasts are probably the cause of collapsing of mines.
Explosive Earthquake: These Earthquakes almost always occur due to the testing of nuclear weapons. When a nuclear weapon detonates, a big blast occurs. This results in the release of a huge amount of energy. This probably results in Earthquakes.
Effects of Earthquakes
First of all, the shaking of the ground is the most notable effect of the Earthquake. Furthermore, ground rupture also occurs along with shaking. This results in severe damage to infrastructure facilities.Another significant effect of Earthquake is landslides. Landslides occur due to slope instability. This slope instability happens because of Earthquake.
Earthquakes can cause soil liquefaction.
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■ landslides:
Landslides: Three regions in India are prone to landslides: the Himalayas, the north eastern hill ranges and the Western ghats.
The roots of vegetation hold the soil tightly.thus,deforestation is a common cause behind land slides .a part from humans made reasons,other reasons,behind landslides are river erosions,heavy rainfall and seismic activity such as earthquakes.A landslide includes a wide range of ground movements, such as rock falls, deep failure of slopes and shallow debris flows. The biggest reason for alandslide is that there is a slope and material goes down the slope because of gravity. … rock and soil slopes made weak through saturation by snowmelt or heavy rains.
landslides occur on mountains and hilly areas. Moreover, landslides can cause destruction to man-made things in many ways.
Causes: Gravitational pull, volcanic eruptions, earthquakes can cause landslides. Moreover, soil erosion.
■ Avalanches:
An avalanche (also called a snowslide or snowslip) is a rapid flow of snow down a sloping surface. Avalanches are typically triggered when the forces on the snowpack exceed its strenght, causing failure of snowpack to hold snow. After initiation, avalanches usually accelerate rapidly and grow in mass.
Avalanches occur in the higher elevations of the Himalayas in the states of jammu and kashmir, Himachal pradesh, and Uttrakhand, which are covered with snow throught the year. Onaccount of global warming, avalanches are expected to increase in future.
Moreover, this causes extreme damage to anything that comes in its way. People who live in snowy mountains always have fear of it.
Causes: Avalanches takes places when there is a large accumulation of snow on the mountains. Moreover, they can also occur from earthquakes and volcanic eruptions. Furthermore, the chances of surviving an avalanche are very less. This is because people die of hypothermia in it.
■ Forest fires:
Forest fires are major cause of forest degradation. Very heavy, heavy, frequent forest damages are noticed over 0.8%, 0.14%, and 5.16% of the forest areas , respectively. Thus, 6.17% of the forests are prone to serve fire damage. In absolute terms, out of the 63 million hectares of forests, an area of around 3.73 million hectares can be presumed to be affected by fires annually.
About90% of the forest fires in India are created by humans. The normal fire season in India is from February to mid-june. India mainly accounts for decidous forests, which are less dense in comparison to equatorial forests. Thus, forests fires are not a frequent phenomenon in India.
the forests become littered with dry senescent leaves and twinges, which could burst into flames ignited by the slightest spark. The Himalayan forests, particularly, Garhwal Himalayas have been burning regularly during the last few summers, with colossal loss of vegetation cover of that region.
Causes of Forest Fire
Forest fires are caused by Natural causes as well as Man made causes.
Natural causes – Many forest fires start from natural causes such as lightning which set trees on fire. However, rain extinguishes such fires without causing much damage. High atmospheric temperatures and dryness (low humidity) offer favorable circumstance for a fire to start.
Man made causes – Fire is caused when a source of fire like naked flame, cigarette or bidi, electric spark or any source of ignition comes into contact with inflammable material.
Classification of Forest Fire
Forest fire can broadly be classified into three categories;
Natural forest fire.
Forest fires caused by heat generated in the litter and other biomes in summer through carelessness of people and
Forest fires purposely caused by local inhabitants.
■ Cloud burst:
Cloud burst refers to an extreme amount of rainfall that last no longer than a few minutes but is capable of creating flood like conditions. “Cloud burst ” is often used to describe a sudden heavy rainfall for a brief period.
According to meteorologist, rainfall equal to or greater than 10cm/h refers to a cloud burst. Cloud burst can take place in a region. Be its mountains or desert. Cloud burst occurs mainly in the Himalayan region. Cloud burst occurs when
One or more of the following conditions take place:
• warm moist air is suddenly exposed to a large amount of cold air, resulting in condensation.
• warm air undergoes sudden condensation when warm wind are required to rise due to the presence of Mountains .cloud burst are most frequent in high altitudes in the Himalayan region.
However, cloudbursts are infrequent as they occur only via orographic lift or occasionally when a warm air parcel mixes with cooler air, resulting in sudden condensation. At times, a large amount of runoff from higher elevations is mistakenly conflated with a cloudburst. The term “cloudburst” arose from the notion that clouds were akin to water balloons and could burst, resulting in rapid precipitation. Though this idea has since been disproven, the term remains in use.
■ Flash flood:
A flash flood is a rapid flooding of low lying areas. flash floods are distinguished from regular floods by a timescale of less than 6 h. it may be caused by heavy rain associated with a sever thunderstorm, or melt water from ice, or snow flowing over ice sheets. flash flood may occur after the collapse of a natural ice or Debris is Dam, or a human structure such as a dam.
The intensity of the rainfall, the location and distribution of the rainfall, the land use and topography, vegetation types and growth/density, soil type, and soil water-content all determine just how quickly the Flash Flooding may occur, and influence where it may occur.
Urban Areas are also prone to flooding in short time-spans and, sometimes, rainfall (from the same storm) over an urban area will cause flooding faster and more-severe than in the suburbs or countryside. The impervious surfaces in the urban areas do not allow water to infiltrate the ground, and the water runs off to the low spots very quickly.
Flash Flooding occurs so quickly that people are caught off-guard. Their situation may become dangerous if they encounter high, fast-moving water while traveling. If people are at their homes or businesses, the water may rise quickly and trap them, or cause damage to the property without them having a chance to protect the property.
■ Tsunami:
Earthquakes, volcanic eruptions and other underwater explosions (including detonations, landslides, glacier calvings, meteorite impacts and other disturbances) above or below water all have the potential to generate a tsunami.[6] Unlike normal ocean waves, which are generated by wind, or tides, which are generated by the gravitational pull of the Moon and the Sun, a tsunami is generated by the displacement of water.
Tsunami waves do not resemble normal undersea currents or sea waves because their wavelength is far longer. Rather than appearing as a breaking wave, a tsunami may instead initially resemble a rapidly rising tide. For this reason, it is often referred to as a tidal wave, although this usage is not favoured by the scientific community because it might give the false impression of a causal relationship between tides and tsunamis. Tsunamis generally consist of a series of waves, with periods ranging from minutes to hours, arriving in a so-called “wave train”.Wave heights of tens of metres can be generated by large events. Although the impact of tsunamis is limited to coastal areas, their destructive power can be enormous, and they can affect entire ocean basins. The 2004 Indian Ocean tsunami was among the deadliest natural disasters in human history, with at least 230,000 people killed or missing in 14 countries bordering the Indian Ocean.
Tsunami refers to the displacement of a large volume of water in the oceans on account of one or more of the following reasons:
• Earthquake
• volcanic eruptions in the oceans
• underwater explosions
• landslides in oceans
• melting of glaciers
• meteorite impacts
In 2004 India experience the massive Tsunami which caused destruction in the coastal areas. This
Tsunami was triggered by an earthquake.
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■ Heat wave:
Heat wave is declared if the maximum temperature rises above 40 degree Celsius for two consecutive days and is at least 4.5 degrees celsius above normal or when the maximum temperature exceed 45 degrees celsius for two days in hilly areas temperature must Rises above 30 degree Celsius with the departure of at least 4.5 degree Celsius.
A heat wave , is a period of excessively hot weather, which may be accompanied by high humidity, especially in oceanic climate countries. While definitions vary, a heat wave is usually measured relative to the usual weather in the area and relative to normal temperatures for the season. Temperatures that people from a hotter climate consider normal can be called a heat wave in a cooler area if they are outside the normal climate pattern for that area.
The term is applied both to hot weather variations and to extraordinary spells of hot which may occur only once a century. Severe heat waves have caused catastrophic crop failures, thousands of deaths from hyperthermia, and widespread power outages due to increased use of air conditioning. A heat wave is considered [extreme weather] that can be a natural disaster, and a danger because heat and sunlight may overheat the human body. Heat waves can usually be detected using forecasting instruments so that a warning call can be issued.
It can also be declared when the maximum temperature goes beyond 47 degrees celsius India saw 1100 heat related deaths in 2016 and more depth than 2200 in 2015.
