Class 9 Geography


Advancing Monsoon

The rainy season begins from early June.

The low-pressure condition over the northern plains intensifies at this time. It attracts the trade winds from the southern hemisphere. These south-east trade winds cross the equator and blow in a south-westerly direction to enter the Indian peninsula as the south-west monsoon. These winds bring abundant moisture to the subcontinent.

The Rainy Season

These winds blow at an average velocity of 30 km/h. The monsoon winds cover the country in about a month; barring the extreme north-west.

Rain in Western Ghats

The windward side of the Western Ghats receives very heavy rainfall, early in the rainy season. The Deccan Plateau and parts of Madhya Pradesh also receive some rain, in spite of lying in the rain shadow area.

Rain in Northeast

The north-eastern part of the country receives the maximum rainfall of this season. Mawsynram (Meghalaya) receives the highest average rainfall in the world.

Rainfall in the Ganga valley decreases from east to west. Rajasthan and parts of Gujarat get scanty rainfall.

Break in Monsoon

Monsoon tends to have breaks in rainfall; which means that there are wet and dry spells in between. The monsoon rains take place only for a few days at a time and then come the rainless intervals. These breaks in the monsoon are because of the movement of the monsoon trough. The trough and its axis keep on moving northwards or southward due to various reasons. The movement of the monsoon trough determines the spatial distribution of rainfall.

The monsoon is famous for its uncertainties. It may cause heavy floods in one part of the country, and may be responsible for droughts in other part. Because of its uncertain behaviour, it sometimes disturbs the farming schedule in India. This affects millions of farmers all over the country.