Compare the Loo, Chinook and Foehn winds with respect to their regions of prevalence, their nature and climatic impacts. (Answer…

Compare the Loo, Chinook and Foehn winds with respect to their regions of prevalence, their nature and climatic impacts. (Answer in 250 words) 15 marks

हिंदी में प्रश्न पढ़ें

लू, चिनूक और फॉन हवाओं की, उनके पाये जाने वाले क्षेत्र, उनकी प्रकृति और जलवायविक प्रभावों के आधार पर, तुलना कीजिए। (उत्तर 250 शब्दों में दीजिए)

The question as printed in the 2026 General Studies paper

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Model answer

Drafted with AI 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. How we build rubrics and answers.

The Loo, Chinook and Foehn are all warm, dry winds, but they differ sharply in region, genesis and impact.

Regions and Seasons The Loo blows over the plains of north-west India and the Indo-Gangetic plain (Punjab to Bihar) in summer, mainly April to June. The Chinook descends the eastern leeward slopes of the Rocky Mountains in North America, and the Foehn the leeward valleys of the European Alps, most famously on the northern side (Switzerland, Austria, Bavaria). Both mountain winds occur mainly in winter and spring, whenever pressure patterns drive air across the mountains.

Nature and Mechanism Chinook and Foehn are orographic downslope winds: moist air sheds precipitation on the windward slope and warms rapidly by dry adiabatic compression as it descends the leeward side. The Loo is non-orographic: a hot, gusty, dusty westerly of continental air heated by intense insolation over the Thar Desert and western plains.

Climatic Impacts The Chinook ("snow eater") and Foehn can raise temperatures by 10–20°C within hours, melting snow, which aids winter grazing on the Prairies and early grape ripening in Alpine valleys, though they also raise avalanche and wildfire risk. The Loo brings severe heatwaves, desiccating crops, causing fatal heatstrokes and spiking power and water demand.

Thus, Chinook and Foehn are topographically driven winds with some agro-climatic benefits, whereas the Loo is primarily an extreme heat hazard.

How this answer will be evaluated

Framework: GS1 Geography: Physical Geography (Winds & Climate)

What earns full marks: Clear table/structure; precise regions; mechanism explained; distinct impacts.

Evaluation rubric

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

The answer Compare the Loo, Chinook and Foehn point by point on regions of prevalence, nature (genesis, season, character) and climatic impacts. 15 marks · 250 words

compare— paired headings or point-wise contrast → key differences → significance → conclusion
Must cover
- Identify specific regions of prevalence for each wind (NW India/Indo-Gangetic plains; eastern Rockies; Alpine leeward valleys)
- Explain nature: orographic adiabatic warming for Chinook/Foehn vs. insolation-heated continental air for the Loo, with seasons
- Detail distinct climatic impacts (e.g., heatstroke and crop stress vs. snowmelt and early grazing/ripening)
- Present a point-by-point comparison on all three parameters
Loses marks
- Narrating chronology instead of comparing features
- Confusing the nature of Loo with Foehn/Chinook
- Listing regions without explaining the 'why' of the mechanism
Earns more
- Local names and areas (Chinook 'snow eater' in Alberta/Montana; Foehn in Switzerland/Austria; Loo in NW India and Pakistan)
- Specific outcomes (heatwave mortality from the Loo; rapid temperature rise and snowmelt from Chinook/Foehn)
- Contrast of triggers: seasonal continental heating (Loo) vs. cross-mountain airflow (Chinook/Foehn)
Extra mark
- 30-second sketch map locating the three wind systems
- One robust statistic on temperature rise or snowmelt rate

What "Compare" is asking you to do

Set the items against each other on named dimensions. In UPSC practice compare already carries both halves — likeness and difference — and where the stem names the dimensions, as in region, nature and climatic impact, those are the headings the examiner expects to see.

Structure that answers it

Dimensions named → both items on dimension 1 → dimension 2 → dimension 3 → where they converge and where they part

Where marks are lost

Two self-contained descriptive blocks with the comparison left for the reader to make. Marks here sit on the dimensions, so an answer that names none of them gives the examiner nothing to award.

All UPSC directive words, compared →

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