Frequency Of Heatwave Increases:
India Meteorological Department (IMD) has predicted an increase in the maximum temperature and the frequency of heatwave conditions in the forthcoming days over eastern and southern India.
- Heat wave is a condition of air temperature which becomes fatal to human body when exposed.
- It is defined based on the temperature thresholds over a region in terms of actual temperature or its departure from normal.
- The IMD will declare a heatwave:
- if the maximum temperature recorded at a station is 40 degrees Celsius or more in the plains, 37 degrees Celsius or more in the coast, and 30 degrees Celsius or more in the hills.
- a heatwave’s severity is determined by its departure from normal temperature.
- there is a ‘normal heatwave’ when the departure is by 4.5-6.4 degrees Celsius and a ‘severe heatwave’ if the departure is greater.
- Heat wave declaration could also be based on actual maximum temperature:
- A ‘heatwave’ is when this figure is greater than 45 degrees Celsius and a ‘severe heatwave’ when greater than 47 degrees Celsius.
- The IMD takes these two ‘routes’ only when at least two stations in a meteorological subdivision report such a high maximum or when at least one station has recorded a corresponding departure from the normal for at least two consecutive days.
