(Vietkings) The city of Cherrapunji is 1,290 meters above sea level and much of the torrential rains run off the mountains into the valley below, which receives an annual rainfall of 1,270 centimeters. Once it rained 2,290 centimeters in one season!
Source: extremescience
What Causes so much Rainfall?
The oceans are the chief source of rain, but lakes and rivers also contribute to it. The sun's heat evaporates the water. It remains in the atmosphere as an invisible vapor until it condenses, first into clouds and then into raindrops. Condensation happens when the air is cooled. For raindrops to form there must be particulate matter in the air, such as dust or salt, at temperatures above freezing. These particles are called condensation nuclei. When the nuclei are cooled to temperatures below the freezing point, water condenses around them in layers. The particles become so heavy they resist updrafts and fall through the clouds as rain.
In Cherrapunji it rains so much for two reasons:
Elevation: because of the elevation of Cherrapunji, air that blows over the plains below is cooled as it rises to the higher elevation. This cooling of the air causes the moisture trapped in the air to condense, forming clouds, which then release rain.
Monsoons: the prevailing winds in that part of the world are very heavily laden with moisture. The constant supply of moist air for six months straight results in almost continual rainfall.
Source: extremescience
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