Briefly mention the alignment of major mountain ranges of the world and explain their impact on local weather conditions, with examples.

Major mountain systems show two dominant alignments, and this orientation relative to prevailing winds largely decides their weather effects.

Alignment of major ranges

• Broadly east–west, along the latitudes: the Alpine–Himalayan chain — Pyrenees, Alps, Caucasus, Hindu Kush, Himalaya — together with the Atlas and Kunlun.
• Broadly north–south, along the longitudes: the American cordilleras — the Rockies and the Andes, running nearly pole to pole — plus the Urals, the Western Ghats and Australia's Great Dividing Range, which walls the moist east coast off from the dry interior.

Impact on local weather

• Climatic divides: the east–west Himalaya walls off cold Central Asian air, keeping north Indian winters milder, and forces the monsoon to precipitate — Mawsynram's record rainfall — while separating monsoonal India from the arid Tibetan interior.
• Orographic rain and rain shadow: the north–south Western Ghats drench windward Konkan while the leeward Deccan stays semi-arid; the Andes back the hyper-arid Atacama; New Zealand's Southern Alps divide a wet west coast from dry Canterbury plains.
• Local winds: adiabatically warmed descending winds — the Chinook east of the Rockies, the 'snow-eater' that lifts Prairie winter temperatures, and the Fohn in Alpine valleys aiding early grape ripening; the cold Mistral funnels between the Alps and Massif Central down the Rhone valley.
• Meridional air movement: because the Rockies run north–south, polar air sweeps unhindered to the Gulf of Mexico, causing severe cold waves in the US interior, whereas Europe's east–west Alps block such incursions and shield the Mediterranean.
• Valley-scale effects: mountain-valley breezes and temperature inversions create frost pockets, which is why Himalayan and Alpine orchards sit on slopes rather than valley floors.

Alignment thus determines whether mountains act as climatic barriers, rain-makers or wind corridors, imprinting sharp weather contrasts across short distances.