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M.PavithraTAM-2013-05Dept. of Agronomy

Heat waves and their management

It is a prolonged period of excessive heat, often accompanied by excessive humidity.

Heat waves occurs when there are a number of consecutive days with above average temperature, that the body can not tolerate.

The unusual and uncomfortable hot weather can impact on human and animal health and cause disruption to community infrastructure such as power supply, public transport and services.

Heat wave

Why should we care about heat?

Heat waves kill and injure Heat wave is one of the major

disaster for many countries, develops slowly and kills and injures many animals and people more than any other disaster.

Hence called as silent disaster

In India the condition becomes more severe in May and June

As the temperature rises , people , animals and plants suffer from heat stress

Apart from death , every day more and more people are admitted with suffering sunstroke and severe dehydration, vomiting and high fever.

Heat wave caused unfold mystery to people all over the world. In 1998, about 1500 people were died in China and in 1997 about 2000 people fell into heat wave in Greece

Similarly in India the heat wave took 302 lives in the year 1998 and more than 2000 people in the year 2002. In Orissa, heat wave caused 2042 deaths in 1998 and more than 1200 deaths in 2002 in southern India

Data collected by IMD reveals that the average annual loss of human life due to heat wave over India is 153

Sunburn Pale skin Heat cramps Heat exhaustion Heat stroke Weakness Fainting/collapse

Nausea Headache Dizziness Rapid pulse drowsiness

Signs and symptoms of heat related illness

Effect on human beings In many parts of world , every summer, thousands of people suffer

from heat stress where their bodies absorb more heat than they expel.

Depletion of salt and electrolyte in the body may cause heat cramp.

Hard work under direct sun may lead to heat exhaustion. Usually, it is the cumulative effect of hot days without the relief of

cool nights and exposure to exhaustion.

Sunburn can retard the body’s ability to shed heat, and may increases the severity of the heat disorder

In severe heat there is dehydration and body may overheat, leading to a heat related illness.[HYPERTHERMIA]

A heat related illness may result in irreversible damage to body, including the brain or even death.

Asphalt and concrete store heat longer and gradually releases heat at night, which produces significantly higher night temperatures in urban areas known as the urban heat island effect.

Urban Heat Island Effect

Who’s most at risk?

Children

Outdoor workers (construction, roofers, migrant workers)

Military

Elderly (especially urban)

Effect on animals

Like human beings, animals too suffer, particularly when they are left in direct sun and they do not get adequate water.

Domestic animals and poultry birds are particularly vulnerable to heat wave.

When there is not enough shade or water for animals, they may change their behavior.

Animals will look for shelter from the heat under trees or near bushes, start sweating and panting, drooping, drink more water and have reduced appetite for food.

Agriculture and cropHeat waves also damage plants, crops and vegetables. When shearing winds blow and the temperature rises to around 45 ⁰ C, exotic plants perish.

When temperature exceeds 45 ⁰ C for a number of days even the traditional species suffer, particularly if they do not receive moisture regularly.

In the grazing field not a single blade of grass is available for the cattle.

During heat wave, the railway lines can expand to the point where they buckle and cause derailment of train.Road damages can also occur with bitumen melting and having cracks.

Long periods of extended heat can soften and crack the asphalt in roads and streets. Concrete and highways have been known to shatter explosively from periods of excess heat. Even bridges may have similar type of damages.

Infrastructure

During hot summer water consumption increases drastically and often causing shortage of drinking water.

Lack of water in most of the wells, pond, tube well and other bodies during hot summer seasons, which has an adverse effect on human being and animal population.

Water

During a heat wave algae growth rates increase, which lowers the oxygen content of the water. The reduced oxygen level combined with heat stress can lead to large scale mortality in wild fish.

Drought conditions from a heat wave increases the occurrence of wildfires. Wildfire kills many animals and destroys the vegetation.

Continued heat wave conditions can also cause crop failure due to lack of rain.

Prevention during heat waveHeat waves can be serious but it is one of the disasters, which can be managed easily.

1. Control the temperature at home

2. In the street, avoid direct sunlight

3. Take care of pets and other animals by avoiding direct exposure to sun

4. Keep rooms cool by using shade cloth or reflective material on the outside of the window

5. Limit physical activity at the hottest times of the day

Drink a lot of water about 2 to 3 litres daily.

Listen to local weather forecast so that we can know if a heat wave is on the way

Avoid heavy protein foods like meat, dairy products etc., which raise body heat and increase fluid loss

If you must go out then wear light weight, light coloured, loose, porous clothes, a wide brimmed hat and sunscreen and regularly rest in shade and drink fluids

Do not leave children or pets in parked vehicles. Temperature inside a closed vehicle can reach over 140 F within minutes. Exposure to such ⁰ high temperatures can kill in minutes

The Heat Index

The state and district control rooms should make necessary arrangement for flashing the warning through all forms of media

Simultaneously, departments like health and other related departments need to remain alert and put necessary emergency measures in place

Interview local officials and representatives of the Department of Agriculture about special steps farmers can take to establish alternative water supplies for their crops and ways to protect livestock and poultry from the extreme heat

Thank you