Idukki has some of the wettest places in Kerala (~ 5000 mm & above) rainfall annually. Peermade and Ponmudi are much known heavyweights to public with rainfall between 4000 – 5000 mm. But Kallar Estate, Rajamalai and Pettimudi in Idukki gets even higher rainfall than Peermade. Rajamalai crossed 9000 mm rainfall for three times in 2000-2010 while Pettimudi clocked 8000 mm twice between 2013-2015, thats almost makes theses places one of the wettest places in South India, giving tough fights to legends in Karnataka such as Agumbe, Hulikal, Talacauvery and Amagaon.
Rajamalai Annual Rainfall (available years)
2004 – 9074 mm
2005 – 9364 mm
2006 – 7731 mm
2007 – 9291 mm
Pettimudi has an annual rainfall average of 5500 mm makes it one of the wettest place in Kerala, only few stations in Kerala such as Kallar Esate (Idukki), Kakkayam Dam (Kozhikode), Rajamalai (idukki), Lakkidi (Wayanad), Walakkad (Silent Valley) gets more rains. Though Neeriyamangalam is used in many places to record as wettest in Kerala, it is not, Walakkad in Silent Valley is the wettest place in Kerala without a doubt and will easily top Neeriyamangalam in Eranakulam district. Sadly most these rainfall are not available to public, I have been tirelessly tracking them for 15 years now with whatever comes in public domain. Even during the worst Elnino drought year of 2015, Pettimudi manged to clock over 6500 mm rainfall. So when monsoon winds are strong like in 2018, 2019 and 2020 August, they get huge rainfall being a closed locked valley trapping all moisture.
Pettimudi Annual Rainfall (available years)
2013 – 8052 mm
2014 – 8023 mm
2015 – 6504 mm
As you can see, places like Pettimudi are extraordinary places in plant earth with extreme monsoon rains falling in short period of time. In the early hours of August 7, 2020, a deadly landslide at Pettimudi, If we look at the rainfall, the rainfall which happened in Pettimudi (24hrs) from August 6 to August 7 early morning was massive 616 mm, this was even bigger 24 hrs event than what happened in 2018 and 2019 in Idukki district. In 1600 mm in just 96 hours is massive even for ghats. This shows how the strong the spells were starting from 4th August. The rains peaked on 6th August, on the 24hrs ending 7th August, 2020 morning nearly 616 mm of rainfall was fallen, that early morning was when the deadly sad event occurred in Pettimudi. Some sources say that it is the highest 24 hrs rainfall in 40 years in that belt. How coincidence, that previous night on 6th August, my FB post says landslides are possible. No one would have expected it to happen in Pettimudi.
Past deadly 4 day events in Kerala
Pettimudi region is prone to heavy rainfall and extreme rainfall at the same time 1600 mm rainfall in 96 hours is no joke. Only the 1924 event in Thalayar in Idukki saw more higher rainfall. With the available data with me, i have compiled the 4 day events (min 700 mm+) and it shows the Pettimudi 4day rainfall in 2020, might be 2nd highest 96 hours event of all time for Kerala next only to 1924 event.
Note: if the image is not clear, save it and zoom them and see.