Two people from a tour group, who were visiting Bhoothathankettu and Thattekad, were washed away near Anakkayam in Periyar on Sunday afternoon.
The missing persons are Peter 45, from Pandikudi, Fort Kochi, and Vyasakh, 35, from Nazareth, Mattancherry, while 38-year-old Shiju, from Mattancherry, who was also swept away, was rescued by Johnson, a local resident.
The two missing persons were part of a 29-member group of a charitable trust. Fire and rescue service, police and forest department personnel have launched a search to trace the missing persons. The water level was very high and there was a strong current due to rain.