What is a cold wave & what triggers them in north-west India?

  • North India may witness the chilliest / extremely cold winter due to the La Nina that has been emerging in the Pacific Ocean. The new forecast warns of an impending La Nina effect that will lead to a major dip in temperature across north India in January, February 2022
Definition of cold wave
  • The IMD defines a cold wave qualitatively as “a condition of air temperature which becomes fatal to the human body when exposed.”
  • According to the IMD, cold wave conditions occur when the mercury falls below 10 degrees Celsius in the plains, and the minimum temperature stays at least 4.5 degrees to 6.4 degrees Celsius below the normal level.
Cold waves over India
  • From December to February, the country is prone to cold waves.
  • Cold waves are more likely to occur in India’s northwestern regions.
  • The arrival of very cold air from the far northwestern areas of the Indian subcontinent, or even further, is linked to the occurrence of cold waves.
India’s Core Cold Wave Zone
  • India’s ‘core cold wave zone’ covers Punjab, Himachal Pradesh, Uttarakhand, Delhi, Haryana, Rajasthan, Uttar Pradesh, Gujarat, Madhya Pradesh, Chhattisgarh, Bihar, Jharkhand, West Bengal, Odisha, Telangana.
Reasons Behind Cold Waves Formation
  • Snowfall in the upper Himalayas-Wind chill factors are caused by snowfall in the upper Himalayas.
  • Absence of cloud cover in the region- Clouds trap some of the outgoing infrared radiation and radiate it back downward, warming the ground
  • Western Disturbances: Western disturbances, which are extratropical storms that mainly occur during the winter months, are rare. The chilly winds from the Himalayas are continuing to blow into northern India, allowing the current frigid temperatures to persist and worsen.
  • Storms that originate in the Mediterranean region and bring winter rains to northwest India are known as Western disturbances.
  • The Pacific’s La-Nina Effect- La Nina is characterized by unusually cool sea surface temperatures along the equatorial Pacific Ocean, which is believed to favor cold waves.
    • La Nina is the abnormal cooler sea surface temperature reported along the equatorial Pacific Ocean and it is known to favor cold waves.
    • Clouds catch some of the outgoing infrared heat and reflect it downward, warming the ground.
    • The Siberian High and the North Atlantic Oscillation (NAO).
The effect of a cold spell
  • Impact on Human Life: Cold waves raise the chance of catching the flu and can cause symptoms such as nosebleeds and a runny nose. In many regions of North India, it was also blamed for the second wave of COVID 19.
    • In 2020, human deaths due to cold waves were 76 times more than those due to heatwaves, according to the India Meteorological Department (IMD).
    • As many as 152 deaths were recorded due to cold waves in 2020 in comparison to just two deaths as a result of a heatwave as per the data of the Ministry of Statistics.
    • Coronary heart disease, cerebrovascular accidents, and respiratory diseases are the most common causes of death associated with cold waves.
  • Impact visibility:The cold wave can affect the visibility and which can be more prone to accidents, loss of life due to accidents.
  • Effect on agriculture in North India: It widens the temperature range between day and night, resulting in irregular winter conditions that wreak havoc on agricultural practices throughout the Rabi season.
  • Impact on Cash Crops: It may have an impact on the production of cash crops such as coffee, which is grown mostly in south India (coffee growth is particularly sensitive to temperature changes).
  • Impact on weak, vulnerable, and marginalized sections
    • The frequency and severity of occurrence of cold waves and their severity is dependent on factors like the geographical location and the climatic conditions of the region.
    • Most vulnerable are those who are in the susceptible age groups like the very young and the old or the infirm.
    • Weaker sections of the society who cannot afford to ensure protection against the extremes of weather are also among the easy targets of the extreme weather conditions.
  • Impact on Daily Life- When the temperature in Himalayan regions drops, electricity and power supplies are disturbed, and water pipes freeze, affecting water delivery.
    • Roads become clogged due to frost, resulting in traffic jams, which reduce human output and bring life to a halt for a period of time.
Road ahead
  • India recognized the cold wave as a disaster in 2012. But action plans are yet to be prepared in many of the cold wave-prone states.
  • Preparedness and mitigation– A cold wave action plan must be formulated to strengthen mitigation and preparedness measures in states with recurrent incidences of cold waves.
    • Vulnerable crops may be sprayed with water that will paradoxically protect the plants by freezing and absorbing the cold from surrounding air.
    • People can stock up on food, water, and other necessities before a cold wave. Some may even choose to migrate to places of milder climates, at least during the winter.
  • Designing policies for the vulnerable sections-Though there are plans and policies to address cold wave preparedness and mitigation, the challenge remains to design a policy exclusively addressing the needs of the urban poor concerning cold wave impact.
    • In Serbia, measures like collecting people (especially the poor and elderly) in communal shelters. Even the homeless may be arrested and taken to shelters, only to be released when the hazard abates. Hospitals can prepare for the admission of victims of frostbite and hypothermia; schools and other public buildings can be converted into shelters.
  • Urban and peri-urban centers must be cold-resilient in which urban local bodies, policymakers, and decision-makers have a major role- Suggested by NDIM.
  • Best policies should be adopted- Clear policies at the national, state, district, and local levels need to be developed to address urban poor needs during the cold wave. Deaths due to cold waves are preventable and the country must prioritize actions to save human lives.
    • In some places, such as Siberia, extreme cold requires that fuel-powered machinery be used even part-time must be run continuously. Internal plumbing can be wrapped, and persons can often run water continuously through pipes.
  • Prevention-The best way to prevent illnesses is, however, to avoid prolonged exposure to the outdoor environment during cold-wave conditions.
    • Most people can dress appropriately and can even layer their clothing should they need to go outside or should their heating fail. They can also stock candles, matches, flashlights, and portable fuel for cooking and wood for fireplaces or wood stoves, as necessary.
    • However, caution should be taken as the use of charcoal fires for cooking or heating within an enclosed dwelling is extremely dangerous due to carbon monoxide poisoning. Adults must remain aware of the exposure that children and the elderly have to cold.


POSTED ON 11-02-2022 BY ADMIN
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