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General Studies 2024 GS Paper I 15 marks 250 words Compulsory Explain

GS Paper I — Q16

What is a twister? Why are the majority of twisters observed in areas around the Gulf of Mexico? (Answer in 250 words) 15

हिंदी में प्रश्न पढ़ें

ट्विस्टर क्या है? मैक्सिको की खाड़ी के आसपास के क्षेत्रों में अधिकतर ट्विस्टर क्यों देखे जाते हैं? (उत्तर 250 शब्दों में दीजिए)

Q16 of the 2024 UPSC Mains General Studies GS Paper I, as printed
The question as printed in the 2024 General Studies paper
Evaluate your answer to this question → See all 2024 General Studies questions

Model answer

Written by UPSC Answer Check against this question's marking rubric, to the 250-word length. UPSC does not publish answers for Mains — this is one way to score well, not an official key.

A twister is a colloquial term for a tornado—a violently rotating column of air extending from the base of a cumulonimbus cloud to the ground. Characterised by extreme low central pressure and destructive winds, its intensity is measured on the Fujita and Enhanced Fujita (EF) scale.

Drivers of Twister Concentration around the Gulf of Mexico

The vast plains extending north from the Gulf of Mexico, spanning traditional Tornado Alley and Dixie Alley, experience the world's highest twister density due to distinct air-mass dynamics:

Moisture and Heat Source: The Gulf of Mexico, with sea surface temperatures exceeding 26°C, supplies buoyant, moisture-laden maritime tropical (mT) air northward.

Air Mass Collision: The flat terrain of the Great Plains lacks east-west topographic barriers, permitting the unobstructed collision of warm Gulf air with cold, dense continental polar (cP) air descending from Canada and dry air from the Rocky Mountains. This sharp boundary creates severe atmospheric instability.

Jet Stream Dynamics: Strong vertical and horizontal wind shear from the polar jet stream tilts thunderstorm updrafts, generating rotating mesocyclones within parent supercells that spawn tornadoes.

Seasonality and Shifting Patterns: Twisters peak during spring (March to May) when latitudinal temperature gradients are steepest. Recent climatic trends show an eastward shift of high-frequency zones toward the humid Southeast.

Comparative Context and Significance

In contrast, India experiences rare tornadoes—such as the deadly Bengal twisters of 1963 and 1978—because the Himalayan barrier blocks polar air incursions, preventing similar thermodynamic clashes. With climate change intensifying atmospheric instability and moisture fluxes, strengthening Doppler weather radar coverage and impact-based early warning systems is vital for disaster risk reduction.

What "Explain" is asking you to do

Make the working of something clear — what sets it off, what follows from what, and what it produces. Explain is the Commission's mechanism word: it dominates the technical papers and the “explain why” stems, where the marks sit in the causal chain and not in the label.

Structure that answers it

State what it is → the initiating condition → the chain of cause, step by step → an instance where it plays out → what the chain produces

Where marks are lost

Describing what something looks like instead of why it works that way. Naming the stages without linking them reads as description too.

All UPSC directive words, compared →

How this answer will be evaluated

Approach

Framework: Geography: mechanism first, location follows. explain: definition/context > points in order > small example > short close Full marks: Precise definition plus clear mechanism of air mass convergence and jet stream shear.

Key points expected

  • Define twister as a rotating air column
  • Explain warm Gulf air mass convergence
  • Mention dry air from Rockies/Plains
  • Link jet stream shear to tornado formation

Evaluation rubric

Each sub-part is marked on its own, against the marks and word limit printed on the paper.

  1. The answer Define twister and explain the meteorological conditions causing high frequency in the Gulf of Mexico. 15 marks · 250 words

    explain— definition/context → points in order → small example → short close

    Must cover

    • Define twister as a rotating air column
    • Explain warm Gulf air mass convergence
    • Mention dry air from Rockies/Plains
    • Link jet stream shear to tornado formation

    Loses marks

    • Confusing twister with hurricane
    • Listing locations without explaining mechanism
    • Vague description of air masses

    Earns more

    • Mention 'Tornado Alley' location
    • Reference spring seasonality
    • Mention CAPE (Convective Available Potential Energy)
    • Reference specific states like Texas/Oklahoma

    Extra mark

    • Sketch map of Tornado Alley
    • Cite specific annual average statistics

Practice this exact question

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