Explained: What is a heatwave and how can you protect yourself from it?

New Delhi: The heatwave has intensified in India with a maximum temperature crossing 45 degrees Celsius in several parts on Thursday. The India Meteorological Department (IMD) notified that a spell of heatwave will persist over northwest and central India for the next five days and over east India for the next three days.

“A rise of about two degrees Celsius in the maximum temperature (is) very likely over most parts of northwest India during the next two days and no significant change thereafter,” the IMD said.

The heatwave has hit the country at a time when the states and Union Territories (UTs) are facing a power crisis. Besides, on Thursday, the country experienced peak power demand or the highest supply in a day. It touched the all-time high of 204.65 GW.

IMD has already issued an orange alert for Rajasthan, Delhi, Haryana, Uttar Pradesh, and Odisha.

Here are some Frequently Asked Questions (FAQs) regarding heatwave:

What is a heatwave?

As per IMD, the heatwave is a condition of air temperature which becomes a risk to the human body when exposed. Quantitatively, a heatwave can be defined as temperature thresholds over a region in terms of actual temperature or its departure from normal.

What are the criteria for declaring a heatwave?

A heatwave is declared when the maximum temperature of a plain region reaches 40 degrees Celsius or more and at least 30 degrees Celsius for hilly regions.

The period of a heatwave in India

Heatwave most occurs between March and June. However, in some areas, a heatwave can also occur in July, according to the IMD. The peak month of the heatwave in the country is in May.

What are the heatwave prone states in India?

These are the heatwave-prone states in India – Punjab, Haryana, Delhi, Uttar Pradesh, Bihar, Jharkhand, West Bengal, Odisha, Madhya Pradesh, Rajasthan, Gujarat, parts of Maharashtra and Karnataka, Andhra Pradesh, and Telangana.

Kerala and Tamil Nadu experience heatwaves sometimes as well.

What can be done to protect yourself from heatwave?

• Drink sufficient water as often as possible, even if not thirsty.
• Avoid going out in the sun, especially between 12 noon and 3 pm.
• Avoid strenuous activities when the outside temperature is high. 
• Wear lightweight, light-coloured, loose, and porous cotton clothes.
• Avoid alcohol, tea, coffee, and carbonated soft drinks, which dehydrate the body.
• Keep your home cool, use curtains, shutters, or sunshades, and open windows at night.
• Use fans, and damp clothing and take bath in cold water frequently.