Hurricanes, Floods and Droughts – Types, Vulnerability

Key Concepts:

• Natural hazards
• Hurricane
• Floods
• Droughts

Introduction: 

Natural hazards are dangerous. They cause severe weather and climate conditions. Even though they occur in all parts of the world, some parts of the world are more vulnerable to particular hazards than others. Natural hazards become calamities when people’s lives and livelihoods are destroyed. 

Disasters are severe disturbances to the functioning of a community that go beyond its capacity to cope using its own resources. Disasters can be triggered by natural, man-made and technological hazards, as well as various other factors that affect the exposure and susceptibility of a community. 

A natural disaster is a natural happening, such as an earthquake, flood, or hurricane, which severely affects community, either by damage to property or by loss of life.  

Landslides, floods, drought, fires are socio-natural hazards because their sources are both natural and man-made. For example, flooding may be caused due to heavy rains, landslides or blocking of drains can occur due to human waste. 

Manmade hazards are caused due to human negligence. They are connected with industries or energy production facilities and comprises of explosions, leakage of toxic waste, pollution, dam failure, wars, or civil strife etc. 

Vulnerability: 

Vulnerability can be defined as the level to which a society, structure, services, or geographic area is likely to be damaged by the effect of particular hazard, based on their nature, construction and closeness to hazardous environments or a disaster-prone area.  

Vulnerabilities can be divided into two types – physical and socio-economic vulnerability.  

Physical Vulnerability:  

It involves ideas of who and what may be damaged by natural hazards like earthquakes or floods. It depends on the physical condition of people and components at risk, like buildings, infrastructure etc., and their closeness to hazardous area, location, and nature of the hazard. Vulnerability is also related to the technical ability of building and structures to withstand the forces acting upon them at the time of hazard.  

Socio-economic Vulnerability:  

The extent to which a population has got affected by a hazard will not simply depend on the physical factors of vulnerability but also on the socioeconomic circumstances. The socio-economic condition of the people also controls the intensity of the impact of hazard. For example, Poor people who are living in the seacoast will not have the money to build concrete houses. Such people will be usually at risk and lose their homes every time when there is strong wind or hurricane.  

Natural Hazards: 

Cyclones/ Hurricane 

Tropical cyclones are fast-rotating storm systems that go (counter-clockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere) around a low pressure centre. Generally cyclones are slow moving but becomes dangerous, with speed of winds between 120-320 kilometres/hour.  

They have various names depending on their location. For example: cyclones in Southeast Asian waters and the Indian Ocean is called cyclone. In East Asian and Pacific waters, it is called typhoons and in the Atlantic, Gulf of Mexico or Caribbean sea, it is called hurricanes. In South America, it is called tornado. Cyclones in the North Atlantic ocean are known as typhoon. Majority of the  cyclone-related deaths are from flooding, electrocution, building collapse and blowing debris. 

Hurricanes are the most destructive and dangerous storms occur on the surface of the Earth. The most dangerous side of hurricane is rising sea levels with huge waves called storm surge. A storm surge can flood low lying coastal areas, hence most of the deaths caused by hurricanes are caused due to drowning. 

Each hurricane is grouped on the Saffir -Simpson scale by using a number of factors, such as central pressure, speed of wind, and storm surge. The Saffir-simpson scale consists of 5 categories. They are  – 1. Storms that cause very less destruction to category 5 – storms that cause devastating damage. 

A completely developed hurricane comprises of series of thick cumulonimbus cloud bands that spiral upward all around the center of the storm. The speed of wind increases towards the center of the storm (also called eye) and it reaches the speed of almost up to 275 km/hr all along the wall of eye. The eye is an area of calm, clear, sinking air. 

A typhoon is a huge, rotating storm that brings gusty wind, rain, and devastation. Hurricanes and typhoons are both forms of tropical cyclones. 

List of some of the disastrous hurricanes: 

Tornadoes are consequences of powerful thunderstorms that seem as rotating, funnel-shaped clouds. They develop from a thunderstorm to the ground with intense winds with the speed of average 30 miles/hour. Similarly, they can change in speed significantly from being stationary to 70 miles/hour. In the USA, with a loud sounds that are similar to a cargo train, the tornadoes are 500 feet across and go on the ground for five miles. Every state will be at some danger from tornadoes and the dangerous storms that produce them. These devastating storms also produce strong gusts of wind, lightning, and flash floods. 

Tornadoes barely give enough time to take shelter or save ourselves because it can hit quickly with little or no warning at all. Due to this unpredictable nature of tornadoes and severe storms, it is very natural for people to suffer through emotional pain. There are some general reactions to such type of disaster and they  are feeling of helpless, great anxiety, insomnia, depression-like symptoms. 

Other indications of emotional suffering related to tornadoes and severe storms contain: 

• Worrying a lot or feeling guilty but not sure about the reason.  
• Feeling helpless or pathetic  
• Thinking that something bad is going to take place while predictions for any storm are announced.  
• Continuous screaming or fighting with family members and friends.  
• Having bad dreams or thoughts and memories associated with the storm. 

Floods

Floods are the situations when water overflows from the normal limits of a stream, river or other sources of water or accumulates in an area that is generally dry. There are two types of floods:  

Inundation floods:  

These are slow, developing over hours or days. 

Flash floods: 

These occur unexpectedly, often without any warning. These are generally caused due to heavy rain. However annual flooding naturally occurs in many parts of the world. Human habitat and usage of land for various practices have led to an increase in frequency and magnitude of floods. In future floods may become more frequent and serious due to climate change. Floods can be very hazardous and cause huge human, environmental and material loss to people. 

Effects of floods: 

Lots of people become homeless and get washed down along with their pets and cattle in the floods.  

Diseases like cholera, gastro-enteritis, hepatitis, and other water-borne diseases spread in the flood-affected areas and can even lead to death of the people. 

Drought

Drought is an prolonged period when there is a shortage of water availability due to insufficient rainfall, increased rate of evaporation and over-utilisation of water from the reservoirs and other storages, including the ground water. 

Drought is a complex situation as it includes components of meteorology such as rain, evaporation, evapotranspiration, ground water, moisture content of soil, storage and surface run-off, agricultural practices, especially the types of crops cultivated, socio-economic practices and ecological situations. 

Types of Droughts  

Meteorological Drought:  

It is a condition when there is a prolonged period of insufficient rainfall observed with mal distribution of the same over a period of time.  

Agricultural Drought:  

It is also called soil moisture drought. It is characterized by low soil moisture content that is essential to maintain the crops, thereby results in failure of crop. Suppose if an area has more than 30% of its overall cropped area below irrigation, then the area is eliminated from the drought-prone category. 

Hydrological Drought:  

This type of drought results when the availability of water in different storages and reservoirs like aquifers, lakes, reservoirs, etc. falls below the level where the rainwater can refill. 

Ecological Drought:  

When the productivity of a natural ecosystem goes down due to shortage of water ecological distress is generated in the ecosystem. 

Effects of Drought: 

Droughts have severe effects on various parts of the environment and society. Crop failure due to drought leads to scarcity of food grains, fodder is most devastating. The most common sight to be seen in the drought affected areas are death of many cattle’s and other animals, and relocation of humans and livestock.  

Scarcity of water makes people to drink contaminated water that results in spread of many waterborne diseases such as gastro-enteritis, cholera, hepatitis, etc. Droughts have both short term and long-term disastrous effects on the social and physical environments.  

Summary:

• Disasters are serious disturbances to the functioning of a community that goes beyond its capacity to manage, using its own resources.
• Naturally occurring physical phenomena is called natural hazards.
• Man-made and technological hazards are incidents that are caused by humans and occur in or close to human settlements.
• Vulnerability can be defined as the extent to which a society, structure, services, or geographic area is expected to be damaged by the effect of particular hazard.
• Tropical cyclones are fast-rotating storm systems that go (counter-clockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere) around a low pressure centre.
• Tornadoes are consequences of powerful thunderstorms that seem as rotating, funnel-shaped clouds.
• Hurricanes are the most destructive and dangerous storms occur on the surface of the Earth.
• Hurricane is grouped on the Saffir -Simpson scale by using a number of factors, such as central pressure, speed of wind, and storm surge.
• The most dangerous side of hurricane is rising sea levels with huge waves called storm surge.
• Floods are the situations when water overflows from the normal limits of a stream, river or other sources of water or accumulates in an area that is generally dry.
• Drought is an prolonged period when there is a shortage of water availability due to insufficient rainfall increased rate of evaporation and over- utilisation of water from the reservoirs and other storages, including the ground water.
• Droughts have severe effects on various parts of environment and society.