Question

With reference to western disturbances, consider the following statements:

1. The Western Disturbance originate over the east Mediterranean sea and travel westtward.

2. The moisture content of the Western Disturbance gets augmented from the Caspian Sea in the north and Persian Gulf in the south.

3. The Western disturbance is regarded as highly beneficial for Rabi crops in North India.

Which of the above statement is/are correct?
1. 1 and 2 only
2. 1 and 3 only
3. 2 and 3 only
4. 1,2 and 3 only

Answer 1

Correct Answer - Option 3 : 2 and 3 only

The correct statement is 2 and 3 only.

• The Western Disturbance originate over the east Mediterranean sea and travel eastward across West Asia. Hence, statement 1 is incorrect.
• The moisture content of the Western Disturbance gets augmented from the Caspian Sea in the north and Persian Gulf in the south. Hence, statement 2 is correct.
• The Western disturbance are highly regarded as beneficial for Rabi crops in North India. Hence, statement 3 is correct.

• Western Disturbances develop in the mid latitude region (north of the Tropic of Cancer), not in the tropical region, therefore they are called as mid latitude storms or extra-tropical storms.
• Extra-Tropical Cyclones are also called as winter storms and blizzards.
• Western Disturbances are low pressure systems, embedded in western winds (westerlies) that flow from west to the east.
• It is a term coined by an Indian Meteorologist for the weather phenomenon which is propagated from the West.
• The phrase Western Disturbance was first used in a published literature in 1947. However, its precursor Winter Disturbance was coined earlier in 1931.

Arrival in India

• Western Disturbances begin is a low pressure system that originates in the Mid- latitude region near the Atlantic ocean and Europe.
• The low pressure typically forms over the Mediterranean Sea and travels over Iran, Iraq, Afghanistan and Pakistan before entering India loaded with moisture.
• These moisture laden western disturbances eventually come up against the Himalayas and get blocked, as a consequence, the moisture gets trapped and precipitation is shared in the form of snow and rain over Northwest India and sometimes, other parts of North India.
• An average of 4-5 western disturbances form during the winter season and the rainfall distribution and amount varies with every western disturbance.