COLD WAVES - GEOGRAPHY
News: What
is a cold wave, why northwest India is shivering
What's in the news?
● Delhi and other parts of
northwest India have been reeling under a cold wave
spell that set in last week.
● The
Delhi has recorded cold wave conditions for five consecutive days so far this
month, making it the longest such spell
in a decade.
● The
lowest minimum temperature recorded this month was 1.9 degrees Celsius on
January 8, the second-lowest minimum temperature in January in 15 years.
Key takeaways:
● While
lower-than-normal temperatures were recorded over parts of Northwest India from
the last week of December, these conditions intensified in the first week of
January.
● Fog and low cloud
coverage brought severe cold day conditions to the
region, when temperatures remained below normal over parts of Delhi, Punjab,
Haryana, Chandigarh, Himachal Pradesh, Rajasthan, Uttar Pradesh and Madhya
Pradesh.
What is a cold wave?
● Cold
wave is characterized by a rapid and marked fall of temperature. The term
‘cold’ describes an unusual fall in
temperature that is triggered by the transport of cold air masses into a
specific area.
● The
IMD marks a cold wave in terms of minimum temperatures - when the minimum temperature in the plains is 4
degrees or less or when the minimum temperature is less than 10 degrees and
4.5 to 6.4 degrees below the normal.
Factors contributing to cold waves:
1. Large scale fog cover:
It lasts for longer durations, preventing sunlight from reaching the surface
and affecting the radiation balance.
2. Light winds and high moisture near the land surface
have been contributing to the formation of a blanket of fog over large swathes
of the Indo-Gangetic plains in the morning.
3. Cold westerly and northwesterly winds
of around 5 to 10 kmph in the afternoon above the surface causing a dip in
temperature.
4. Western disturbances,
which are storms from the Mediterranean region, are associated with a change in
wind direction, bringing easterly winds to northwest India. Western Disturbance
can be defined as “a low pressure area or a trough over surface or the
upper-air in the westerly winds regime, north of 20°N, causing changes in
pressure, wind pattern and temperature fields. It is accompanied by cloudiness,
with or without precipitation.”
5. Climate Change:
The unusually cold December this year could just be another instance of extreme
climates. Across the world, the frequency and intensity of both heatwaves and
cold waves have increased in the last few years.
6. Low Clouds:
This extended cold spell has been triggered due to low stratus clouds that are
blanketed over a large geographical area between Pakistan, cutting across India
and running up to Bangladesh.
7. Snowfall in the upper Himalayas
are responsible for the wind chill factors.
8. La-Nina Effect in the Pacific:
La Nina is the abnormal cooler sea surface temperatures reported along the
equatorial Pacific Ocean and it is known to favour cold waves.
Impacts of Cold waves in India:
1. Agriculture:
It affects the productivity of rabi and cash crops (Coffee, Tea).
2. Health:
The cold wave is extremely fatal to human health, it could affect vulnerable
people (infants, pregnant women, elderly, people) with chronic diseases.
Likelihood of illnesses like flu, due to prolonged exposure to the cold.
3. Impact visibility:
The cold wave can affect the visibility and which can be more prone to
accidents, loss of life due to accidents.
4. Livestock:
During a cold wave, the animals require a higher intake of nutrition.
5. Energy sector:
The impact on the energy sector is well marked with a rise in the demand for
fuels and electricity during cold wave conditions.
Measures:
● Considering
the importance of cold wave, the Government of India notified ‘cold wave’ as a disaster and the Ministry
of Agriculture as the nodal Ministry for cold wave/ frost.
● Accordingly,
the Ministry of Home Affairs included cold wave/ frost as an eligible natural
calamity in the guidelines for relief assistance under the SDRF / NDRF, and the
financial assistance is limited to the agriculture sector only.
● Cold Wave Action Plan
(CWAP) is prepared by the National Disaster
Management Authority (NDMA).
WAY FORWARD:
NDMA Guidelines:
● Provision
of adequate winter clothing.
● Staying
in indoors as much as possible.
● Weather
forecast and early warning systems.
● Taking
care of vulnerables such as elderly people and children.
● Providing
ways for seamless provisions of emergency supplies.