Briefly mention the alignment of major mountain ranges of the world and explain their impact on local weather conditions, with examples.
Approach · directive: “briefly mention / explain”
What it asks · First state the alignment of major ranges (east-west or north-south), then link that alignment to rainfall, temperature and wind patterns with examples.
The question has 2 parts — answer each
- Briefly mention the alignment of the world's major mountain ranges
- Explain their impact on local weather — rainfall, temperature, winds, local circulation — with examples
Open with · The alignment of a range to the prevailing winds decides whether it blocks moist air or channels it, creating sharp climatic contrasts over short distances.
Cover
- Alignment: Himalaya, Alps and Pyrenees run broadly east-west; Rockies, Andes, Urals, Western Ghats and Great Dividing Range north-south; Appalachians and Atlas south-west to north-east.
- Orographic rain and rain shadow: Western Ghats (wet west coast, dry Deccan interior), southern Andes (wet Chile, dry Patagonia), Sierra Nevada (dry Great Basin).
- Himalayan barrier: shields north India from Central Asian cold, holds monsoon clouds for heavy southern rain, and leaves cold desert in Tibet and Ladakh.
- Winds: foehn in the Alps and chinook east of the Rockies bring warm, dry, snow-melting winds down leeward slopes.
- Altitude: temperature falls with height, so high ranges carry snow and glaciers and zoned climate and vegetation (Alps, Andes, Himalaya).
- Local circulation: valley and mountain breezes, valley temperature inversions and fog (Kashmir, Alps), and convective storms and cloudbursts on steep slopes.
- Impacts on people: snow-fed rivers, farming on windward slopes and hazards such as avalanches and floods shape settlement and livelihoods.
Close with · Alignment relative to prevailing winds is the key: windward slopes are wet, leeward slopes dry, and high ranges act as climatic divides.
Question: UPSC's CS (Main) 2021, GS Paper I — paper ↗. Approach: Minimalist IAS, checked 30 Sept 2026 (how we verify) — UPSC publishes no model answers. ·
Model answer · 293 words (UPSC limit 250) · Minimalist IAS
A range's alignment relative to the prevailing winds decides whether it blocks moist air, channels it or shelters the land behind, producing sharp climatic contrasts over short distances.
Alignment of major ranges
- East-west: the Himalaya, Alps and Pyrenees, lying across north-south air movement.
- North-south: the Rockies, Andes, Urals, Western Ghats and Great Dividing Range, lying across the westerlies, trades or monsoon winds.
- Oblique: the Appalachians and the Atlas run south-west to north-east.
Impact on local weather
- Orographic rain and rain shadow: windward slopes force moist air to rise and cool, leeward slopes stay dry — the wet west coast of India against the dry Deccan interior across the Western Ghats; wet southern Chile against dry Patagonia across the Andes; the Great Basin in the shadow of the Sierra Nevada.
- Climatic barrier: the Himalaya shields north India from Central Asian cold waves, holds monsoon clouds for heavy rain on its southern slopes, and leaves Tibet and Ladakh as cold deserts.
- Local winds: the foehn in the Alps and the chinook east of the Rockies descend leeward slopes as warm, dry winds that melt snow and raise temperatures within hours.
- Altitude: temperature falls with height, so high ranges carry snow, glaciers and vertical zones of climate and vegetation, as in the Alps, Andes and Himalaya.
- Local circulation: valley and mountain breezes, night-time temperature inversions and fog in valleys such as Kashmir and the Alps, and convective storms and cloudbursts on steep slopes.
- Impact on people: snow-fed rivers, farming concentrated on windward slopes, and hazards such as avalanches and flash floods shape settlement and livelihoods.
Alignment relative to the prevailing winds is the key: windward slopes are wet, leeward slopes dry, and high ranges act as climatic divides shaping rainfall, temperature and livelihoods on either side.
Written by Minimalist IAS from facts checked at source (how we verify) — a little fuller than exam length, so every part of the question is covered; in the hall, keep the structure and trim the detail. UPSC publishes no model answers: compare your structure and coverage with this, then write your own.