Why Coonoor Gets Heaviest Rainfall during North-east Monsoon
Generally during North-east Monsoon or Summer Season, when a Low pressure system tracks along Lakshadweep sea, Places along Kerala coast get Rainfall, which lies between 40-100mm QPF. But the places in the Nilgiri District of Tamilnadu, particularly Coonoor-Kothagiri-Ketti Belt gets Heavy rainfall of around 100-120 mm QPF.
One extra-ordinary rainfall,
Orography of Nilgiris-
When during South west monsoon, Coonoor belt is subjected to mild rainfall, where as the other stations like gudalur, portimund Avalanche is subjected to heavy rainfall. During the North east Monsoon, the winds are from east and the Western parts like gudalur, avalanche become dry. But it is noted a heavy rainfall along Coonoor belt. When Synoptic system moves close Kerala coast, Coonoor-Kothagiri belt witness heavy rainfall. Even if we take 2009 as example, a Depression became well marked close to Kerala coast and Nilgiri witnessed extremely heavy rains. One of the heaviest rains in Tamilnadu state, Ketti with 820mm in 24 hours.
