Torrential rain has battered the coastal state of Kerala since Friday, causing rivers to swell and flooding roads that left vehicles submerged in muddy waters, with some houses reduced to rubble.
Rescue efforts have continued since Saturday, with the Indian army, navy and air force assisting. The National Disaster Response Force has deployed 11 teams across south and central parts of Kerala.
Thirteen people were killed in a landslide in the Kottayam district, according to state officials. Nine bodies have also been recovered from the site of another landslide in the district of Idduki, officials said, adding that two people are still unaccounted for. Three fishermen in the Malappuram district also remain missing.
"It's not just the flooding or landslides that have been the cause of death... two people died because they were trapped under a vehicle and two children died due to a wall collapsing," Dr. A. Kowsigan, Commissioner of Kerala's State Disaster Management Authority, told CNN.
Rescue efforts are currently trying to determine the number of missing people, Kowsigan said.
Thousands of people have been evacuated to more than 150 relief camps across the state, according to the Kerala State Disaster Management Authority.
The heavy rainfall was caused by a low pressure area over the southeastern Arabian sea and Kerala, India's Meteorological Department said. The deluge was forecast to ease Monday, but CNN Weather still predicts 50 to 100 millimeters (2 to 4 inches) of rain for the area in the coming days.
The Indian Meteorological Department on Sunday issued alerts for later this week, saying from October 20 an "easterly wave is likely to affect" India's south peninsula, where Kerala is located, "and cause fairly widespread rainfall with isolated heavy falls ... and likely to continue for subsequent [three to four] days."
Home to more than 33 million people, Kerala regularly experiences heavy rainfall during the monsoon months from late May to September. However, flash flooding and landslides have become more frequent and severe in the state in recent years.