The Onset and Withdrawal of the Monsoon


 
 
Concept Explanation
 

The Onset and Withdrawal of the Monsoon

The Onset and Withdrawal of the Monsoon: The trade winds are steady but the monsoon winds are pulsating in nature. They are affected by different atmospheric conditions encountered by it, on its way over the warm tropical area. Starting from early June in the Southern part of the Indian peninsula, the monsoon lasts between 100 and 120 days, withdrawing by mid-September. Rainfall increases suddenly and continues for several days at the time of arrival of monsoon. This phenomenon is called as Burst of monsoon. It is different from pre-monsoon showers. Afterwards, it alternates with wet and dry spells.

Onset of Monsoon: Monsoon generally reaches the Southern tip of the peninsula during the first week of June. After striking the Southern tip, it branches into two parts- the Arabian Sea branch and ‘the Bay of Bengal branch; both branches move rapidly.

  • The Arabian Sea branch advances North along the Western Ghats, reaching Mumbai by about 10th of June and soon covers the Saurashtra-Kuchchh and central most part of the Deccan Plateau also.
  • The Bay of Bengal branch reaches Assam in the first week of June and gets deflected towards the West by the mountain ranges, thus giving rainfall to the Ganga plains.
  • Both the branches again merge over the North-Western part of the Ganga plains. Delhi receives rainfall from Bay of Bengal branch by the end of June (tentative date is 29th June) and by the first-week of July, monsoon covers Western Uttar Pradesh, Punjab, Haryana and Eastern Rajasthan.
  • Withdrawal of Monsoon: Withdrawal or the retreat of the monsoon is a more gradual process. The process begins by early September in North-Western states. By mid-October, it withdraws completely from the Northern half of the peninsula.

    The withdrawal from the Southern half of the peninsula is fairly rapid. By early December, the monsoon has withdrawn from the rest of the country.

    Onset and Withdrawal of Monsoon in the Indian Islands: The islands receive the very first monsoon showers from the la week of April to the first week of May. The withdrawal takes place progressively from North to South (in reverse direction) from the first week of December to the first week of January. By this time, the rest of the country is already under the influence of the winter monsoon.

    Important Features of Monsoon: The important features of monsoon are:

  • The monsoon is also known for its uncertainties.
  • There is alteration of dry and wet spells which vary intensity, frequency and duration.
  • While it causes heavy floods in one part, it may responsible for drought in other parts.
  • Its irregular arrival and retreat (sometimes due to the effect of EL Nino), causing disruption of farming schedules and causing droughts in certain areas of the country.
  • Sample Questions
    (More Questions for each concept available in Login)
    Question : 1

    Arrange the following states on the basis of ascending dates of the onset of the monsoon ?

    1. Uttar Pradesh

    2. Kerala

    3. West Bengal

    4. Rajasthan

    Right Option : B
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    Explanation
    Question : 2

    What is a mango shower?

    Right Option : A
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    Question : 3

    The monsoon withdraws completely from the _______ part of the Indian peninsular by mid-October

    Right Option : B
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    Explanation
     
     
     


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