Context: 

As per India Meteorological Department (IMD), January of 2024 has been the second driest since 1901.

91% Rain Deficit in Northwest India in January: Second Highest Since 1901

• Rain deficit: The Northwest India region comprising states of  (Haryana, Himachal Pradesh, Punjab, Rajasthan, Uttarakhand, Uttar Pradesh, and the National Capital Territory) has received only 7.8 mm rainfall in the months of December and January.
  • January: It reported 1.2 mm against normal of 32.5 mm rainfall (-91 per cent).
  • December: It witnessed  6.6 mm rainfall  against the normal of 18.9mm (-65 per cent) 
• Dry winters: The higher reaches of Jammu and Kashmir, Ladakh, Himachal Pradesh, Uttarakhand and neighboring hilly terrains have experienced complete absence of snowfall this season.
• Reason:
  • Feeble Western disturbance: This season witnessed five such disturbance streams but their position and intensity remained unfavorable for the country, therefore  the precipitation remained significantly below normal
  • El- Nino emergence: El Nino’s impact is evident in Kashmir  through prolonged dry spells, milder winters, and diminished snowfall. India’s monsoon rainfall for the year 2023 hit a five-year low, marking the lowest since 2018 due to El Nino. 

About Western Disturbances: 

• A western disturbance (WD) is an extra-tropical storm which originates in the Mediterranean region.
  • Literal Meaning of Western Disturbance: In term WD, the “Disturbance” means an area of “disturbed” or reduced air pressure  while the “Western” implies that the  disturbance travels from the west to the east direction.
• Non-Monsoonal Precipitation Pattern: It is a non-monsoonal precipitation pattern that induces low pressure systems in the lower layers of the atmosphere
• Winter Precipitation in North India:They are responsible for precipitation (snow & rainfall) in north India in Winters and lower the temperatures.
• Recent Trends: There is a declining trend in intensity in the past few years due to changing climate and  is witnessing a southward dip in  causing good rainfall over central India, but either deficient or scanty rainfall over most of northern India.
• Implications: 
  • Rabi crop:  The majority of Rabi crops are sown in the period of  October and November therefore scanty rainfall will affect the yield of Rabi crops in northern regions.
  • Horticulture farming: Apple production will suffer greatly as a result of the prolonged drought and lack of snow. 
  • Water replenishment: Western Disturbances are important for the availability  and replenishment of water along the hilly terrains of the Himalayas and the dependent ecosystem. 
    • Dry winters risk thirsty summers with the water level in rivers and lakes at an all time low.

News Source: The Indian Express

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