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Explained: What are heatwaves & how do they occur?
A heatwave refers to a period of unusually hot weather which lasts for two or more days. The temperatures have to be above the historical average to be considered a heatwave.
India on Saturday continued to swelter and burn under a ferocious heatwave, with maximum temperatures reaching 46 degrees Celsius in some parts. According to the India Meteorological Department, this intense heat will continue until May 2. Alerts - 'yellow' for some areas and 'orange' for others - have been issued for northwest and central India, including Jharkhand. Worse, electricity cuts because of a shortfall in coal supply and exacerbated by spiking temperatures - has compounded the miseries of millions.
What is a heatwave?
A heatwave refers to a period of unusually hot weather which lasts for two or more days. The temperatures have to be above the historical average to be considered a heatwave.
For the plains, a heatwave is declared when max temperature is expected to be over 40 degrees Celsius and at least 4.5 degrees above normal.
How does a heatwave occur?
According to the Farmers' Almanac , a heatwave occurs due to movement of high atmospheric pressure into an area and lasts for two more days.
In such a condition, air from the upper levels of our atmosphere is pulled towards the ground. It then gets compressed and triggers a rise in temperatures. The high pressure makes it difficult for other weather systems to move into the area.
Movement of winds therefore becomes non-existent. The high pressure system also bars clouds from entering the region and sunlight can further heat the system. Such hot temperature conditions are called heatwaves.
ALSO READ: Heatwaves surge across India. Weather office says will get hotter in next 5 days
Are heatwaves fatal?
A heatwave can kill a person due to dehydration resulting from excessive sweating. The change in sodium and potassium concentrations in the blood can confuse both the heart and nerve cells, resulting in difficulties breathing and circulating blood.
ALSO READ: 5 tips to stay cool, healthy in this blistering heatwave
How to protect yourself from heatwaves?
Experts say one should drink sufficient water and avoid going out in the sun between 12 and 3 pm.
You are also advised to avoid drinking alcohol, tea and coffee and keep the home cool by using drapes or curtains to block out the sun.
