Cold Wave

The India Meteorological Department (IMD) has forecast that higher-than-normal cold wave days are likely to impact parts of central India, along with certain regions of northwest and northeast India.

What is a Cold Wave?

A cold wave is an extreme weather event characterised by unusually low temperatures in the near-surface atmosphere.
It occurs due to a rapid fall in temperature within a 24-hour period or the invasion of very cold air masses over a large area.

Cold waves may persist for several days to a few weeks, depending on regional geography and prevailing climatic conditions.

IMD Criteria for Declaring a Cold Wave

The IMD uses both absolute minimum temperature values and departure from normal temperature to declare a cold wave.

Minimum Temperature Threshold

• Plains: Minimum temperature of 10°C or below

• Hilly regions: Minimum temperature of 0°C or below

Departure from Normal Temperature

• Cold Wave: Negative departure of 4.5°C to 6.4°C

• Severe Cold Wave: Negative departure of more than 6.4°C

For plains specifically:

• Cold Wave: Departure of ≤ 4°C

• Severe Cold Wave: Departure of ≤ 2°C

Seasonal Occurrence in India

Cold waves in India are predominantly experienced during the winter months from December to February.
They mainly affect northern, northwestern, central, and northeastern regions, where minimum temperatures often fall sharply during winter.

Health Risks Associated with Cold Waves

Exposure to extreme cold can lead to serious health problems such as:

• Hypothermia and frostbite

• Non-freezing cold injuries, including Immersion Foot, caused by prolonged exposure to cold and wet conditions

• Increased mortality, particularly among vulnerable populations such as the elderly, homeless, outdoor workers, and people without adequate heating or shelter

Conclusion

Cold waves are a significant climatic and public health concern in India.
Timely weather warnings, preparedness measures, and public awareness are essential to minimise their impact on human life and livelihoods.