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Explained | What’s Heatwave And How Can You Protect Yourself From a Heatstroke?

The India Meteorological Department (IMD) said the spell of heatwave will persist over northwest and central India for the next five days and over east India for the next three days.

Updated: April 29, 2022 5:22 PM IST

By News Desk | Edited by Sanstuti Nath

Explained | What's Heatwave And How Can You Protect Yourself From a Heatstroke?
A Liquid Petroleum Gas (LPG) cylinder delivery man drinks water from a bottle during his shift on a hot summer afternoon (Photo/AFP)

New Delhi: The blistering heatwave sweeping through vast swathes of the country intensified on Friday with the mercury crossing the 45-degree mark at several places. Three Indian cities, including Haryana’s Hisar (46 degrees Celcius), Punjab’s Patiala (45.9 degrees Celcius) and Prayagraj in Uttar Pradesh (45.9 degrees Celsius), were among the top 5 hottest places in the world today. The India Meteorological Department (IMD) said the 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,” it said. The weather agency has also issued an orange alert for Rajasthan, Madhya Pradesh, and the Vidarbha region of Maharashtra for the next three days.

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What Is A Heatwave And How Weather Warnings Are Mapped?

The IMD uses four colour codes for weather warnings. Green means no action needed, yellow refers to watch and stay updated, orange means be prepared while red alert means take action.

A heatwave is declared when the maximum temperature is over 40 degrees Celsius and at least 4.5 notches above normal. A severe heatwave is declared if the departure from normal temperature is more than 6.4 notches, according to the IMD. Based on absolute recorded temperatures, a heatwave is declared when an area logs a maximum temperature of 45 degrees Celsius. A severe heatwave is declared if the maximum temperature crosses the 47-degree mark.

According to weather experts, temperatures may even leap to 47 degrees Celsius in parts of northwest India. “A maximum temperature of 45 degrees Celsius is normal at places like Rajasthan’s Churu, Barmer, Bikaner, and Sri Ganganagar, but 45-46 degrees Celsius in the plains of north India by April-end is quite unusual,” independent meteorologist Navdeep Dahiya said.

How Does Heatwave Affect Heath?

The IMD said the heatwave could lead to “moderate” health concerns for vulnerable people such as infants, the elderly and people with chronic diseases. “Hence people should avoid heat exposure, wear lightweight and light-coloured cotton clothes and cover the head with a hat or umbrella,” it said.

There is an increased likelihood of symptoms of heat illness in people who are either exposed to the sun for a prolonged period or doing heavy work, an IMD advisory read.

Dileep Mavalankar, the director of the Indian Institute of Public Health Gandhinagar (IIPHG), said, “People need to watch out for IMD advisories, stay indoors, keep themselves hydrated and rush to the nearest health centre if they feel moderate signs of heat-related illness.”

“There’s a special need to monitor the old and vulnerable just like we did during the COVID-19 waves as they can develop heat strokes even when sitting at home,” he said.

Mavalankar said that cities should monitor all-cause mortality data daily along with that of hospital admissions and ambulance calls to compare it with the last five years of data to get a real indication of heat stress on mortality.

Early heatwaves have a higher rate of mortality since adaptation and preparedness is low during March and April, he said.

Dos During Heatwave

  1. Stay indoors and in shaded places as much as possible
  2. Wear thin loose cotton, light-coloured garments.
  3. Cover your head with an umbrella/hat/cap/towel when outside.
  4. Drink water and salted drinks (lassi, lemon water, fruit juices, ORS) frequently.
  5. Eat fruits such as watermelon, cucumber, lemon, orange etc.
  6. Take frequent cool baths and reduce room temperature.
  7. Use window shades/curtains, fan, cooler, air-conditioner, cross-ventilated room, sprinkle water, keep indoor plants etc.
  8. If a person feels unwell, especially the elderly, children, pregnant women, and those with pre-existing medical conditions, they should immediately shift to a cooler place, put on minimum clothing, be sponged with cold water and be transported to the nearest health facility.

Don’t During Heatwave

  1. Avoid going out in the sun, especially between noon and 3 pm
  2. Avoid doing strenuous activities when outside in the afternoon.
  3. Avoid drinking alcohol, tea, coffee and carbonated soft drinks
  4. Don’ leave children or pets in parked vehicles.
  5. Don’t wear dark-coloured, synthetic and tight clothing, as they absorb more heat.

Heatwave Situation Across India

Large parts of India have been recording higher than normal temperatures since the last week of March, with weather experts attributing it to the absence of periodic light rainfall and thundershowers, typical for this time of the year, due to the lack of active western disturbances.

Northwest India saw at least four western disturbances in March and April, but they were not strong enough to cause a significant change in weather, said Mahesh Palawat, Vice President (Meteorology and Climate Change), Skymet, a private weather forecasting agency. The region did not see any significant pre-monsoon activity from March 1 to April 20 which compounded the severity of successive heatwave spells, he said, adding it had a ripple effect on central India, too.

Vidarbha in Maharashtra and west Rajasthan have consistently reported maximum temperatures in the range of 40 degrees Celsius to 45 degrees Celsius for the past two months.

India saw its warmest March since the IMD began keeping records 122 years ago amid a 71 per cent rain deficit. Having recorded three prolonged heatwave spells, it could be one of the hottest April in the history of the country, Dahiya said.

(With Agency Inputs)

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