Briefly mention the alignment of major mountain ranges of the world and explain their impact on local…

Question

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

Ghissu Editorial · Accepted Answer

Major ranges run either east-west, like the Alpine-Himalayan belt, or north-south, like the Rockies, Andes and Western Ghats, and their angle to the winds shapes rainfall, cold barriers and local winds. Windward Mahabaleshwar receives over 5,000 mm of rain while leeward Pune lies in a rain shadow.

**Introduction**

Mountain ranges follow plate boundaries, and their alignment against prevailing winds decides where rain falls, where cold is held back and where deserts form.

**Alignment of the Major Mountain Ranges**

1. **East-west Alpine-Himalayan belt**: The Atlas, Alps, Caucasus, Zagros and Himalaya run east to west along the old Tethys suture.
2. **North-south ranges**: The Rockies and Andes line the western Americas, and the Urals, Great Dividing Range and India's Western Ghats also run broadly north-south, while the Aravallis trend north-east to south-west.

**Impact on Local Weather Conditions**

1. **Orographic rain and rain shadow**: Windward slopes get heavy rain and leeward slopes stay dry, so Mahabaleshwar receives over 5,000 mm while nearby Pune gets under 1,000 mm.

SKETCH: comparison | Windward vs Leeward Slope
a: Windward slope
b: Leeward slope
- Rising, cooling air :: Sinking, warming air
- Heavy orographic rain :: Rain shadow
- Mahabaleshwar :: Pune
- Cloudy, humid :: Dry, clear

2. **Cold barrier**: The Himalaya blocks Siberian air from the northern plains, whereas North America's open north-south corridor lets Arctic and Gulf air clash, breeding tornadoes.
3. **Parallel alignment**: The Aravallis run parallel to the monsoon, fail to lift it, and leave western Rajasthan dry.
4. **Local winds**: Descending Chinook winds on the Rockies and the Foehn in the Alps warm leeward slopes sharply, the Chinook by over 20 degrees Celsius within hours, and valley inversions bring fog and frost to Kashmir.

**Way Forward**

1. **Mountain forecasting**: Himalayan Doppler radars can track cloudburst-producing convection like Kedarnath 2013.
2. **Rain-shadow planning**: Watershed development and drought-resilient crops suit leeward Marathwada and interior Karnataka.

**Conclusion**

Mountain alignment quietly controls local weather, deciding where rain falls and deserts form, so reading terrain with weather is central to climate-resilient planning.

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

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