The Great flood of '99 (Malayalam:'തൊണ്ണൂറ്റി ഒമ്പതിലെ വെള്ളപ്പൊക്കം' (Thonnootti Onbathile Vellapokkam) occurred when the Periyar River in Kerala state of India flooded in the month of July 1924. This happened in the year 1099 ME in the Malayalam Calendar (Kollam Era). As the Malayalam Calendar was popular in Kerala, the flood is generally referred to as "The Great flood of "99".The rain continued for about three weeks. Many districts of present-day Kerala were deeply submerged by the flood - from Thrissur, to Ernakulam to Idukki, Kottayam even up to Alappuzha and Kuttanad. A huge mountain called Karinthiri Mala was washed away by this flood and the road to Munnar also went along with it. As the road to Munnar was lost by this flood, a new road from Ernakulam to Munnar became necessary - the present day road from Ernakulam to Munnar was constructed after this. Kundala Valley Railway which was the first monorail system in India was also completely destroyed. Various remnants of the old Railway systems still exist at Munnar.