Climate Hazard & Vulnerability Atlas of India

The India Meteorological Department (IMD), Ministry of Earth Sciences has brought out a web based online ‘Climate Hazard & Vulnerability Atlas of India.

The primary purpose of the Climate Vulnerability maps is for the users of disaster management sectors to identify the vulnerable districts for taking preventive and adaptive measures. Thus, in vulnerability maps, vulnerability assessment was focused at the district levels.

About the maps

The Climate Hazard & Vulnerability Atlas of India has been prepared for the thirteen most hazardous meteorological events, which cause extensive damages, economic, human, and animal losses. For a visual display of the Climate Vulnerability maps, Geographic Information System (GIS) tools have been used at the office of Climate Research and Services, India Meteorological Department Pune.

Total 640 maps are available in this web version of Climate Vulnerability Atlas. The following data are considered for analysis

• Disaster data from IMD publication “Annual Disastrous Weather Event” for the period 1967 – 2019. This publication provides information on the disaster events and their casualties in terms of human loss as per media reports and other official reports from various government agencies.
• IMD Climatological Normal for various meteorological parameters for the period 1981-2010.
• Hourly autographic data and three hourly synoptic hours data of surface meteorological stations of IMD.
• IMD Best Track Cyclone data for the period 1981-2020
• IMD digital Cyclone track data from Cyclone e Atlas for the period 1871- 2020 provided by RMC Chennai. 
• Daily District rainfall data of IMD for the period 1901-2020.
• Daily rainfall data for more than 9000 rain gauge stations for the period 1901-2020.
• Census data of population density and housing density for cyclone vulnerability 
• Storm surge data from reports of RSMC, New Delhi 

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Climate Hazard Maps

Dust storm

Dust storms are common meteorological hazards in arid and semi-arid regions. It is usually caused by thunderstorms or strong pressure gradients associated with cyclones which increase wind speed over a wide area. These strong winds lift large amounts of sand and dust from bare, dry soils into the atmosphere, transporting them hundreds to thousands of kilometers away. Some 40% of aerosols in the troposphere (the lowest layer of the earth’s atmosphere) are dust particles from wind erosion. Airborne dust presents serious risks for human health. Dust particle size is a key determinant of the potential hazard to human health. Particles larger than 10 μm are not breathable, thus can only damage external organs – mostly causing skin and eye irritations, conjunctivitis, and enhanced susceptibility to ocular infection. Inhalable particles, those smaller than 10 μm, often get trapped in the nose, mouth, and upper respiratory tract, and thus can be associated with respiratory disorders such as asthma, tracheitis, pneumonia, allergic rhinitis, and silicosis. However, finer particles may penetrate the lower respiratory tract and enter the bloodstream, affecting all internal organs and being responsible for cardiovascular disorders.

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Hail storm

Typically, hail is a cascading effect of a thunderstorm event. A hailstorm is an outgrowth of a severe thunderstorm in which balls or irregularly shaped lumps of ice fall with the rain. Extreme temperature changes from the ground upward into the jet stream produce strong updraft winds that cause hail formation. Hailstorms are usually considered “severe” when hail is larger than 1” and accompanied by winds greater than 58 miles per hour. The severity of hail events range based on the size of hail, winds, and structures in the path of a hailstorm. Storms that produce high winds in addition to hail are most damaging and can result in numerous broken windows and damaged siding. Hailstorms can cause extensive property damage affecting both urban and rural landscapes. These can cause damage to crops, livestock, and wildlife and can cause extensive damage to buildings, including roofs, windows, and outside walls. Vehicles can be total losses. When hail breaks windows, water damage from accompanying rains can also be significant.

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Thunderstorm

A thunderstorm is a type of storm with lightning and thunder. They are caused by an updraft, which occurs when warm, moist air rises vertically into the atmosphere. The updraft creates a cumulus cloud, which will eventually be the thunderstorm cloud. The basic factors that form a thunderstorm are moisture, unstable air, and a Lifting mechanism. Every thunderstorm produces lightning, which kills more people each year than tornadoes. Heavy rain from thunderstorms can lead to flash flooding, strong winds, hail, and tornadoes are also dangers associated with thunderstorms.

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Fog

Fog is a visible aerosol comprising tiny water droplets or ice crystals suspended in the air at or near the earth’s surface. Nearby bodies of water, topography, and weather conditions are three factors that influence fog. Fog formation starts when the air near the earth’s surface becomes saturated. Air in this area becomes saturated by any of these three processes: cooling, the addition of moisture, and mixing with another air parcel. Depending on the concentration of the droplets, visibility in fog can range from the appearance of haze to almost zero. Many lives are lost each year worldwide from accidents involving fog conditions on the highways, including multiple-vehicle collisions. The aviation travel industry is affected by the severity of fog conditions. Fog is also having an impact on health. Vapor in the fog impacts breathing adversely. But generally, smog which is a combination of fog and smoke has a dangerous effect on health.

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Lightning

Lightning is an electrical discharge caused by imbalances between storm clouds and the ground or within the clouds themselves. Most lightning occurs within the clouds. In the early stages of development, air acts as an insulator between the positive and negative charges in the cloud and between the cloud and the ground. When the opposite charges build up enough, this insulating capacity of the air breaks down and there is a rapid discharge of electricity that we know as lightning. The flash of lightning temporarily equalizes the charged regions in the atmosphere until the opposite charges build up again. Lightning can set off building or farm fires, damage electrical equipment, and electrocute humans and livestock. Lightning can enter your home by following wires and pipes that go into the ground; it can also travel through metal reinforcing wire or bars in concrete and explode. Lightning often knocks out power lines and sends powerful electrical surges through electrical and phone lines. Once in your home, they can burn out appliances and other electronics.

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Wind Hazard

Extreme wind that may be associated with any weather systems like thunderstorms, cyclones etc is one of the major hazards to the society as the extreme wind can damage any structure, including the building of various types, electrical infrastructure, telecom industry, agriculture, and forest as well as transport and other sectors.

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Extreme rainfall Events

Rainfall events of high intensities are in most cases cause by floods, waterlogging, landslides and many other disasters. information of maximum probable frequencies (number of days) of extreme rainfall events (heavy, very heavy, or extremely heavy) of each district from the past record of more than 100 years can identify the districts vulnerable to extreme events.

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Drought:

Drought occurs due to deficiency of rainfall for an extended period of time, resulting in meteorological drought and causing lack of soil moisture leading to extensive damage to crops, loss of yield, resulting in a water shortage causing adverse impacts on vegetation, animals, and people.

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Cyclone

It is one of the major meteorological disasters in coastal areas of India. Cyclones are intense low-pressure areas from the center of which pressure increases outwards. The amount of pressure drop in the center and the rate at which it increases outwards gives the intensity of the cyclones and the strength of winds.

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Climate Vulnerability Maps

Heatwave:

The heatwave conditions signify a certain amount of rising of temperature at a given place with respect to normal climatological value. In India, heatwave (HW) conditions are generally experienced during the period from March to July. Annual Disaster Weather Reports published by India Meteorological Department show records of the heatwave cases over India that caused hazards in terms of human death. Disaster data shows that the damages and casualties associated with HWs are observed during the months of May to July.

Heatwave is an emerging public-health problem. Extreme heat can lead to minor illnesses, such as heat rash, heat edema, heat cramps, and tetany, and serious illnesses such as heat syncope, heat exhaustion, and heatstroke. Heatstroke is the most severe form of heat-related illness.

The criteria adopted by IMD to define Heat Wave is given below:

• Heatwave is considered if the maximum temperature of a station reaches at least 40⁰C or more for Plains and at least 30⁰C or more for Hilly regions.
• Based on Departure from Normal Heatwave:
  • Departure from normal is 4.5⁰C to 6.4⁰C
  • Severe Heatwave: Departure from normal is >6.4⁰C
• Based on Actual Maximum Temperature
  • Heatwave: When the actual maximum temperature ≥ 45⁰C
  • Severe Heatwave: When the actual maximum temperature ≥47⁰C c)
• Criteria for describing Heatwave for coastal stations
  • When maximum temperature departure is 4.5⁰C or more from normal, Heatwave may be described, provided the actual maximum temperature is 37⁰C or more.

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Flood:

Floods are associated with heavy to very heavy or extremely heavy rainfall for a spell from 1 day to 3 days or even more than three days. Also, some floods like flash floods and urban floods occur due to occurrences of intense rainfall for a very short duration of time. Some areas are even flooded due to intense rainfall in the upper catchment or due to the release of water from the dam or reservoir. Floods have an impact on both individuals and communities and have social, economic, and environmental consequences. The consequences of floods, both negative and positive, vary greatly depending on the location and extent of flooding and the vulnerability as well as the value of the natural and constructed environments they affect. The immediate impacts of flooding include loss of human life, damage to property, destruction of crops, loss of livestock, and deterioration of health conditions owing to waterborne diseases. As communication links and infrastructure such as power plants, roads, and bridges are damaged and disrupted, some economic activities may come to a standstill, people are forced to leave their homes, and normal life is disrupted.

In the present vulnerability map for flood, we are showing the total number of flood events during the period of disaster data. In addition, the Normalized Vulnerability Index is being calculated for each district as per the formula mentioned in equation.

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Lightning:

Lightning is an electrical discharge caused by imbalances between storm clouds and the ground or within the clouds themselves. Most lightning occurs within the clouds. In the early stages of development, air acts as an insulator between the positive and negative charges in the cloud and between the cloud and the ground. When the opposite charges build up enough, this insulating capacity of the air breaks down and there is a rapid discharge of electricity that we know as lightning. The flash of lightning temporarily equalizes the charged regions in the atmosphere until the opposite charges build up again. Lightning can set off building or farm fires, damage electrical equipment, and electrocute humans and livestock. Lightning can enter your home by following wires and pipes that go into the ground; it can also travel through metal reinforcing wire or bars in concrete and explode. Lightning often knocks out power lines and sends powerful electrical surges through electrical and phone lines. Once in your home, they can burn out appliances and other electronics.

Annual Disaster Weather Report published by India Meteorological Department reports the lightning cases over India that caused hazards in terms of human death. Though actual lightning cases were more, only the cases that caused human death were reported during February to October and are considered in our analysis. For each of nine months and annual scale, maps are showing the total number of lightning days that caused casualties to humans. In addition, the Normalized Vulnerability Index is being calculated for each district as per the formula mentioned in equation 1.

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Snowfall:

Snow is formed from condensed water on the atmosphere. Water vapour in clouds condenses to form droplets. Cold air then freezes the water to form ice crystals. As these ice crystals bind with more water vapour they become heavier. Eventually, the ice crystal falls from the cloud, collecting more water vapour as it falls. As the ice crystal descends and the air temperature increases, the ice crystal can melt slightly. This melting can cause crystals to bind together to form larger flakes. Snow will remain on the ground if the temperatures are cold enough to keep it from melting. Snowfall is another hydrological hazard as a large amount of snow can affect transport routes, crops, and people. The secondary risks of snowstorms include vehicle accidents, hypothermia, infections from frostbite and possibly fires, and carbon monoxide poisoning due to the use of alternate heat sources.

Annual Disaster Weather Report published by India Meteorological Department reports the snowfall cases over India that caused hazards in terms of human death. Though it starts in some parts of the country in November month in some years, the disaster data shows that the damages and casualties happened during the months of December to February. For each of three month and annual scale, there are maps showing the total number of snowfall days that caused casualties to humans. In addition Normalized Vulnerability Index is being calculated for each district as per formula mentioned in equation 1.

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Cold wave

The cold wave conditions signify a certain amount of fall of temperature at a given place with respect to normal climatological value. In India, the cold wave (CW) conditions are generally experienced during the period from November to March. However, the disaster data shows that the damages and casualties are associated with CWs during the months of December to March. It has a severe impact on human health, varying from Cough and cold, bronchitis and respiratory diseases, Blood pressure issues, Skin problems, and even Bone, joint, and muscle pain due to lack of sunlight. The health conditions, particularly of the poor people, are seriously affected, and in extreme cases even it causes casualty.

The criteria adopted by IMD to define Cold Wave is given below:

• Cold Wave is considered when the minimum temperature of a station is 10⁰C or less for plains and 0°C or less for Hilly regions.
  • Based on Departure Cold Wave:
    • Negative Departure from normal is 4.5°C to 6.4°C
    • Severe Cold Wave: Negative Departure from normal is more than 6.4°C
  • Based on Actual Minimum Temperature (For plain stations only)
    • Cold Wave: When minimum temperature is ≤ 04°C
    • Severe Cold Wave: When minimum temperature is ≤ 02°C b)
• Cold Wave conditions for coastal stations
  • When minimum temperature departure is -4.5°C or less over a station. “Cold Wave” may be described if the minimum temperature is 15⁰C or less.

Annual Disaster Weather Report published by India Meteorological Department reports the cold wave cases over India that caused hazards in terms of human death. Though actual cold wave cases were more, only the cases that caused human death were reported and are considered in our analysis. For each of four months and annual scale, there are two maps showing the total number of cold wave days that caused casualties to the humans, and the Normalized Vulnerability Index calculated for each district as per the formula mentioned in equation 1.

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Source : IMD