"Kerala is facing its worst flood in 100 years. 80 dams opened, 324 lives lost and 223139 people are in about 1500+ relief camps," read a tweet from the Chief Minister's Office.

Till now, 42 Navy, 16 Army, 28 Coast Guard and 39 National Disaster Relief Force teams were engaged in rescue operations. Another 14 NDRF teams are expected to reach shortly. The military has pushed in more than 200 boats. Another four aircraft and three Coast Guard ships have also been brought in.

"I spoke to the defence minister this morning and asked for more helicopters," Mr Vijayan told a news conference in state capital Thiruvananthapuram earlier on Friday. "In some areas, airlifting is the only option ... thousands are still marooned," he said, adding that he planned to send 11 more helicopters to the worst-hit places.

Flood waters from the Periyar river and its tributaries have submerged many towns in Ernakulam and Thrissur. An alarming situation has developed in Alapuzha, Ernakulam, Thrissur and Pathanamthitta districts, where roads have become completely submerged. Thousands of people are still perched on trees and rooftops, waiting to be rescued.Water has started entering relief camps.

On Friday morning, Prime Minister Narendra Modi tweeted, "Had a telephone conversation with Kerala CM Shri Pinarayi Vijayan just now. We discussed the flood situation across the state and reviewed rescue operations. Later this evening, I will be heading to Kerala to take stock of the unfortunate situation due to flooding."

Desperate non-resident Keralites from Australia, the US and the UK have been pleading with authorities, seeking help for their families.

Though the met office has said the rainfall will continue till today, the intensity has lessened slightly. A tweet from the Chief Minister's Office this morning said, "All districts apart from Kasargod are under red alert. The Meteorological Department warns that heavy rains may affect these 13 districts."

Domestic airlines have been asked to keep a check on air fares for flights operating to and from Kerala. Telecom operators have announced free call and data services and other relief measures for a week for users in Kerala.

Hundreds of fishermen from coastal villages have joined the rescue efforts at Pathanamthitta, where helicopters are airlifting people to safer places.