India, Aug. 13 -- A 100-year flood does not mean a flood that occurs once every 100 years, but one with a 1 per cent chance of occurring in any given year.

Kerala's 2018 flood was compared with the great flood of 1924, creating the impression that such events would not recur soon.

Repeated floods in Kerala since 2018, including flooding along the Pamba and Manimala rivers in 2026, show why that understanding is misleading.

Flood-risk mapping and 100-year flood estimation are now essential for Kerala's infrastructure planning, evacuation preparedness and protection of low-lying communities.

After the great floods of 2018, many in Kerala were relieved by the belief that they would not have to witness another major flood in the near futu...