Thiruvananthapuram,(PTI) Heavy rains in Kerala today claimed 20 lives, leaving a trail of destruction across the southern state.

With water levels rising in various dams and reaching almost its maximum capacity, shutters of at least 22 reservoirs in the state have been opened to drain out excess water.

Of the total deaths, 11 people were killed in a massive landslide in high range Idukki, six in northern Malappuram district, two others in Kannur and one in Wayanad district since last night, disaster control room source said here.

Five members of a family were killed in Idukki's Adimali town.

Two persons were pulled out alive from the debris by the locals and police, they said.

For the first time in the last 26 years, a shutter of the Cheruthoni dam of the Idukki reservoir, considered the biggest arch dam in Asia, was opened by noon today with the water level touching 2,398.98 ft.

The full reservoir level (FRL) of the dam is 2,403 ft.

Four shutters of the Idamalayar dam in Kochi district were opened this morning and people living in the banks of Periyar river and its other tributaries were asked to be vigilant as the released water was likely to inundate low-lying areas.

The government has asked tourists not to go to high range areas and dam sites.

Talking to reporters after a review meeting, Chief Minister Pinarayi Vijayan said the flood situation in the state was "very grim" and it was for the first time in the history of the state that 22 dams have been opened at a time following the water level reaching its maximum capacity.

The annual Nehru Trophy boat race, scheduled to be held at Punnamada Lake in Alappuzha district on August 11, has been postponed due to floods, he said.

"There is a possibility of water level increasing in Kuttanad in the district in the event of the Kakki reservoir lifting shutters. So, the boat race has been postponed. The new date will be announced later," Vijayan said.

He said an assistance of Army, Navy and Coast Guard has been sought and six more columns of National Disaster Response Force (NDRF) had been requested to be deployed in the flood-hit areas.

"The flood has caused large-scale damage across the state. Water levels in rivers are on the rise. Thus, there is a need to open the shutters of many dams," the chief minister said.

The deployment of Navy helicopter has been sought for the rescue of those stranded in the remote areas of Wayanad district, he said.

The Left leader added the services of Army and NDRF had also been sought in the worst-hit Malappuram, Kozhikode, Wayanad and Idukki districts.

A 24x7 monitoring cell has been set up at the Secretariat here to coordinate the relief works with various district collectors.

Members of the central team, who are in the state to assess the damage, held a meeting with the chief minister this morning.

Vijayan said the state would submit a detailed memorandum to the Centre seeking financial assistance for taking up relief works.

Meanwhile, many places in Palakkad town were under flood water.

High range roads in Idukki and Wayanad were damaged due to landslips and uprooting of trees, causing traffic blocks.

Educational institutions have declared a holiday in Idukki, Kollam and other districts of the state.