India is reeling under an intense and deadly heatwave a phenomenon that is likely to worsen in the years to come.
Maharashtra has recorded 374 cases of heatstroke in March and April with 25 deaths, the most in six years. Vidharbha and Marathwada have been the worst-hit regions.
The India Meteorological Department has forecasted severe heatwave conditions for for the first week of May in most of the country, with temperatures expected to cross above normal levels in many places.
Areas in Western Gujarat, Eastern Rajasthan, Punjab, Haryana, Uttar Pradesh, Assam, Tripura, Bihar and Odisha recorded departures of maximum temperatures between 4°C and 5.7°C on April 28. Rajgarh in West Madhya Pradesh recorded the highest temperature last week when the mercury touched 45.6°C on April 27.
What is a heatwave?
The IMD declares a heatwave when the mercury touches 40° Celsius in a station in the plains and 30°Celsius in a hilly region.
A heatwave is also declared when the maximum temperature increases by 4.5°C to 6.4°C than normal.
A severe heatwave is declared when the maximum temperature increased by 6.4°C than normal.
In coastal areas, a heatwave is declared when the maximum temperature increases by 4.5°C when the maximum temperature is 37°C or more
Heatwaves normally occur in India between March and June peaking in May and occasionally extending to July.
What Is The Cause Of The Current Heatwave?
Scientists have said that the current heatwave has been affected by the formation of anti-cyclones over western Rajasthan. Like the name suggests, anti-cyclones are the opposite of cyclones where wind rotates around a high atmosphere pressure system in clockwise direction in the northern hemisphere.
Cyclones are wind systems which rotates around a low atmosphere pressure system in an anti-clockwise direction in the northern hemisphere.
Experts have also attributed the heatwave weak western disturbances which has resulted in little rainfall in the winter months in north and central India.
Western disturbances are low-pressure storm which form over the Mediterranean which bring rains over northern and central India during winter.
The high temperatures have led to an increase in power consumption in the country leading to a coal shortage.
Are heatwaves going to be harsher?
According to a 2017 study, climate change impact will see a rise in deadly heatwaves in northern India with wet-bulb temperatures expected to exceed the critical threshold of 35°C.
At wet-bulb temperature is in a heat index which factors the humidity levels to measure temperature.
A rise in humidity levels is worsening the heatwave. Experts say that a wet-bulb temperature of 35°C is the upper limit of a human being's ability to cool themselves by sweating.
