A heat wave is a period of abnormally high temperatures, more than the normal maximum temperature that occurs during the summer season in the North-Western parts of India, according to the National Disaster Management Authorities. Heat Waves typically occur between March and June, and in some rare cases even extend till July. The threshold for a heat wave is met when the maximum temperature of a weather station reaches at least 40 degrees Celsius in the plains, 37 degrees in the coastal areas and 30 degrees in the hilly regions, and the departure from normal is at least 4.5 notches. A severe heat wave is declared if the departure from normal temperature exceeds 6.4 notches.
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Why do heatwaves happen?
Heatwaves occur due to various factors, often a combination of: > High pressure systems: When high-pressure systems settle over an area, they suppress cloud formation and trap heat at the surface, leading to rising temperatures. > Large-scale weather patterns: Global weather patterns can influence regional climates. For example, a persistent shift in wind patterns can bring hot air masses to a particular area. > Climate change: Rising global temperatures due to climate change contribute to more frequent and intense heatwaves.
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What’s happening in India?
Intense heat is sweeping large swathes of India in April, with maximum temperatures settling four to six degrees Celsius above normal in many areas. According to the India Meteorological Department (IMD), maximum temperatures hovered between 42 and 45 degrees Celsius in parts of Odisha and Rayalaseema, Gangetic West Bengal, Jharkhand, Vidarbha, Chhattisgarh, Madhya Pradesh, Telangana and Andhra Pradesh. The heatwaves are scorching parts of Odisha, Jharkhand, Gangetic West Bengal, Telangana, Andhra Pradesh, Tamil Nadu and Gujarat.
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How to heatwaves affect you?
The health impacts of Heat Waves typically involve dehydration, heat cramps, heat exhaustion and/or heat stroke. The signs and symptoms are as follows: > Heat Cramps: Ederna (swelling) and Syncope (Fainting) generally accompanied by fever below 39°C i.e.102°F. > Heat Exhaustion: Fatigue, weakness, dizziness, headache, nausea, vomiting, muscle cramps and sweating. > Heat Stroke: Body temperatures of 40°C i.e. 104°F or more along with delirium, seizures or coma. This is a potential fatal condition. > Dehydration: Heatwaves increase sweating, leading to dehydration if fluids aren’t replenished. Dehydration can cause fatigue, headaches, and worsen other heat-related illnesses.
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Small tips to stay safe from heatwaves
Here are some precautions to take during heatwaves: > Stay hydrated: Drink plenty of water and cooling beverages throughout the day, even if you don’t feel thirsty. > Limit strenuous activity: Avoid exercising or working outdoors during the hottest part of the day. > Wear loose, lightweight clothing: Opt for breathable fabrics like cotton to allow sweat to evaporate. > Seek air conditioning or cool spaces: Spend time in air-conditioned buildings, libraries, or malls if possible. Take cool showers or baths.
