VARIATIONS IN MONSOON CONDITIONS AT A LOCAL LEVEL:
The amount of rainfall produced by the monsoon is prone to variability for a number of reasons related to the surface of the land the monsoon air is passing over. Mountain ranges, for example, have an influence on the rains of the Indian monsoon.
The range of mountains known as the [P 019 / M001 / Western Ghats], which run along the west coast, have very intense rain on the western side. This is caused by the moist air being forced upwards by the slope, and consequently cooled, causing [G 18 / precipitation]. On the lee slopes, the air is warmed and dried, so producing much less rainfall.
The western slopes of the Ghats have an average annual rainfall of approximately 16.4 feet, whereas the Deccan Peninsula on the lee side has an average of approximately two feet. This is known as the rain shadow effect.
The town of [L3 305 / Cherrapunji], in the Khasi Hills within the state of Meghalaya, experiences [P 007 / extremely heavy rain]. The arm of the monsoon in the Bay of Bengal strikes the Khasi Hills and deposits its moisture there. At the same time, air flowing from the west encounters no obstacles in its path causing it to shed rain until it reaches the Khasi Hills. The area therefore receives a huge amount of precipitation.
Areas of extreme dryness also have an effect on the amount of rainfall. The [M001 / Thar Desert] in Rajasthan is very hot and dry. Moist air moving into this region tends to be dried out to some extent, thereby reducing the amount of rain that falls. There is an Indian proverb about the variability of the rains from area to area: The rains have fallen on one horn of the buffalo and not the other. This expresses neatly the fact that areas close together can get very different amounts of rain.
