GS Paper 1
Syllabus: Geography – Important Geophysical phenomena such as earthquakes, Tsunami, Volcanic activity, cyclones etc
Source: DTE
Context: Recently large parts of the country experienced hailstorms which were also accompanied by torrents of rain.
- The hail and rains have led to extensive damage to standing crops in many states, such as Maharashtra, Rajasthan and Punjab.
Causes:
- The rainfall and the storms were caused by multiple western disturbances (WD), other WD-associated weather systems and many troughs, which are extended low-pressure areas, formed due to the interaction of the WDs and associated systems with winds blowing in from the east, mainly the Bay of Bengal.
- A warming Arabian Sea could also be responsible for the intense storm activity and rain.
- The IMD also cited a strong subtropical westerly jet stream, a band of winds that circles the subtropical regions of the planet in the upper layers of the troposphere, as a reason for the storm activity.
- This was aided by the incursion of moisture-laden winds from the Bay of Bengal and the lowering of the freezing level in the atmosphere, which helped in the formation of hail.
About Western Disturbances:
- Western disturbances are extra-tropical storms that originate in the Caspian or Mediterranean Sea, which is an area of low pressure & bring sudden showers(non-monsoonal), snow and fog to northwest India.
- These travel eastwards on high-altitude westerly jet streams– massive ribbons of fast winds traversing the earth from west to east.
Related News:
Climate change is causing Western Disturbances to weaken; here is how
Source: DTE
Context: Recent studies have shown that the warming of the Arctic and the Mediterranean Sea means that Western Disturbances are striking India less in winter and more in summer; with catastrophic consequences.
Reason for weakening Western Disturbances:
- Climate Change
One of the reasons for the abnormally hot February was the formation of a high-pressure area near the land surface, which caused the air to descend, compress and heat up.
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