Himalayas as a climatic divide
Also called: Himalayas as climatic barrier · Topic: Climate of India and the Monsoon · NCERT: Class 7, Ch 3 "Climates of India"; Class 11, Ch 2 "Structure and Physiography"; Class 11, Ch 4 "Climate"
Meaning
The Himalayas form a high wall along India's north. In winter they block cold winds from the Arctic and Central Asia, so north India stays milder than it would otherwise be. In summer they trap the moist monsoon winds. The winds cannot cross the range, so they drop their rain inside India.
This is why the Himalayas are called a climatic divide: they separate India's climate from the climate of Central Asia. Without them, north India would have harsh Central Asian winters, and much less monsoon rain.
Example
Delhi and the Ganga plain are shielded by the Himalayas from the freezing winter winds of Central Asia. In summer, the monsoon winds moving up the Ganga plain are held back by the range, so they bring rain to Bihar, Uttar Pradesh and the foothills.
Don't confuse with
- Rain shadow area: this is a small dry zone on the sheltered side of a mountain, such as Pune behind the Western Ghats. The Himalayan divide works at the scale of the whole subcontinent.