Heatwaves

Why in the News?

Large parts of Europe, the U.K., and the U.S. are sweltering under extreme heat wave conditions.

Key Points:

Defining Heat Waves:

• • A Heat Wave period is characterised by abnormally high temperatures, more than the normal maximum temperature.
  • A heat wave is announced if the maximum temperature is over 40 degrees Celsius and at least 4.5 notches above normal.
  • A severe heatwave is announced when there is fluctuation of is more than 6.4 degrees from normal temperature or if the maximum temperature crosses 47 degrees, according to the IMD.

Heat Wave Classification in India:

• • On the basis of absolute recorded temperatures, a heatwave is declared when an area records a maximum temperature of 45 degree Celsius.
  • The Indian Meteorological Department, qualitatively classifies a heat wave as one when the air temperature reaches a point that it become fatal to the human body when exposed.
  • Quantitatively, it is defined based on temperature thresholds over a region in terms of actual temperature or its departure from normal.
  • Heat waves generally occur over plains of northwest India, Central, East and north Peninsular India.

Conditions for Heatwave Formation:

• Prevalence of hot, dry air over an area
• Moisture
• Cloudless Sky
• Anticyclonic flow

Factors responsible for Heat Waves formation:

• Lack of Rainfall
• Western Disturbances
• La Nina
• Climate Change
• Dry & Hot Westerly Winds

Impact of Heat Waves:

• Heat-related illnesses
• Poor air quality
• Little rainfall
• Reduced crop yields
• Rise in Power demand
• Melting of Mountain snow
• Forest fires
• Physiological stress

Way Forward:

• Heat waves are not part of a notified disaster, we need to take steps in recognising in that direction.
• An early warning system should be set up to alert citizens about the onset of the heatwave and set inter-agency coordination for practical cooperation.
• Focus should be on building capacity among healthcare professionals, including paramedical staff and community health staff, to ensure that they appear as the first line of defence.
• An array of actions related to urban planning and governance and governmental and community preparedness should be adopted by Cities.