WHY IN NEWS?
- A recent forecast by Indian Meteorological Department’s (IMD) states that there will be warmer-than-usual summer.
WHAT ARE HEAT WAVES?
- According to WHO, a heat wave is defined as five or more consecutive days of prolonged heat in which the daily maximum temperature is higher than the average maximum temperature by 5°C (9°F) or more.
- A heat wave, or heatwave is a period of excessively hot weather, which may be accompanied by high humidity, especially in oceanic climate
- The term is applied both to hot weather variations and to extraordinary spells of hot weather which may occur only once a century.
- According to the IPCC, heatwaves have become more frequent, and over land more intense, almost everywhere since the 1950s, due to climate change.
WHAT IS CRITERION FOR DECLARING HEAT WAVE IN INDIA?
- Heat wave is considered if maximum temperature of a station reaches at least 40°C or more for Plains and at least 30°C or more for Hilly regions.
- Based on Departure from Normal Heat Wave: Departure from normal is 4.50°C to 6.40°C Severe Heat Wave: Departure from normal is >6.40degree C.
- Based on Actual Maximum Temperature Heat Wave: When actual maximum temperature ≥ 450°C Severe Heat Wave: When actual maximum temperature ≥47.
- If above criteria met at least in 2 stations in a Meteorological sub-division for at least two consecutive days and it declared on the second day.
IMPACTS OF HEATWAVES
- Severe heat waves have caused catastrophic crop failures, increased risk of wildfires in areas with drought, and widespread power outages due to increased use of air conditioning.
- Exposure to hotter than average conditions compromises the body’s ability to regulate temperature and can result in a cascade of illnesses, including heat cramps, heat exhaustion, heatstroke, and hyperthermia.
SOURCE : THE STATESMAN
Syllabus : PRELIMS, GS-1, GEOGRAPHY