Heatwave In India: Orange Alert Issued As Delhi Records Hottest April Day In 5 Years

Delhi on Saturday recorded temperature of 42.4 degree Celsius, which was its hottest April day in five years, according to the 
India Meteorological Department.

Previously, Delhi had recorded a maximum temperature of 43.2 degree Celsius on April 21, 2017.

Meanwhile, the highest maximum temperature for the month was recorded on April 29, 1941 at 45.6 degree Celsius.

In its warning, the weather department said that this is for the first time in 72 years that Delhi has recorded such a high temperature in the first half of April.

IMD issues orange alert

IMD said this is the first time in 72 years that Delhi has recorded such a high temperature in the first half of April. The meteorological office has issued an orange alert warning of a severe heatwave in the city on Sunday as well.

The IMD uses four colour codes for weather warnings – green (no action needed), yellow (watch and stay updated), orange (be prepared), and red (take action).The maximum temperature of 42.4 degrees Celsius at Delhi's base station, Safdarjung Observatory, was eight notches above normal for this time of the year.

The weather stations at Ridge, Ayanagar, Mungeshpur, Najafgarh, Pitampura and Sports Complex recorded maximum temperatures of 43.9 degrees Celsius, 43.6 degrees Celsius, 43 degrees Celsius, 43.3 degrees Celsius, 43.4  degrees Celsius and 43.9 degrees Celsius, respectively. Cloudy conditions may bring some relief from the stifling heat from Tuesday, the IMD said.

Parts of the national capital have been reeling under a heatwave since last week with maximum temperatures hovering above 40 degrees Celsius. IMD officials said a prolonged dry spell has led to "severe" hot weather conditions in northwest India. The weather department said northwest India and adjoining parts of central India are predicted to see more intense and frequent heatwave conditions in April.

Extreme heatwave in Northwest India at this time an 'aberration', says expert

At 44.5 degrees Celsius, Gurugram was 10 degrees warmer than average. Gurugram's all-time high maximum temperature of 44.8 degrees Celsius was recorded on April 28, 1979.

The mercury settled at 45.2 degrees Celsius in Haryana's Faridabad. Barring SPS Mayur Vihar, which recorded a high of 40.2 degrees Celsius, all automatic weather stations in the city recorded maximum temperatures above 42 degrees Celsius, IMD data showed.

Mahesh Palawat, vice-president (Meteorology And Climate Change), Skymet Weather, said it is an aberration that the maximum temperature has breached the 45-degree mark in parts of northwest India in the first 10 days of April. There has been nil pre-monsoon activity, including dust storms and thundershowers, in the region so far. Long-range models have also not predicted any significant weather system in the next 15 days, he said. There is a good chance that Delhi may record a higher-than-usual number of heatwave days in April, Palawat said.

The capital has already recorded three heatwave days this month and the ongoing heatwave spell is likely to persist for another two to three days, he said. For the plains, 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.

This year, India recorded its warmest March in 122 years with a severe heatwave scorching large swathes of the country during the month. The weather department attributed the heat to the lack of rainfall due to the absence of active western disturbances over north India and any major system over south India. The country as a whole recorded 8.9 mm of rainfall, which was 71 per cent less than its long period average rainfall of 30.4 mm. It was also the third-lowest precipitation in March since 1901 after 7.2 mm in 1909 and 8.7 mm in 1908.

Why is there a heatwave?

Maximum temperatures in India show a rising trend, starting from southern parts followed by central and northern India. March is the beginning of the summer season over India. During this month, the maximum heating zone runs along central India regions between Odisha and Gujarat. Here, hotter conditions start building up in March.

The maximum temperatures peak in April and May and the India Meteorological Department (IMD) identifies the core heatwave zone spanning Rajasthan, Punjab, Haryana, Chandigarh, Delhi, West Madhya Pradesh, Uttar Pradesh, Chhattisgarh, Odhisha, Vidarbha in Maharashtra, parts of Gangetic West Bengal, Coastal Andhra Pradesh and Telangana.

Hot winds from the deserts of northwest India also contribute to the soaring temperatures in central India regions.

Many places in the northwest and cities along the southeastern coast report up to eight heatwave days per season. However, the regions in the extreme north, northeast and southwestern India are lesser prone to heatwaves.This year, the geographical expanse of the latest heatwave spell was unusually large. Along with seasonal transition, the lack of pre-monsoon showers has contributed to the overall heating.

With PTI inputs