Thiruvananthapuram, Aug 9 The death toll in rain-related incidents over the last 24 hours in Kerala reached 24 on Thursday as Chief Minister Pinarayi Vijayan postponed Saturday's annual Nehru boat race in Alappuzha following forecast of more rains.Following the opening of the Idamalayar dam, the waters flooded the Periyar river and reached the compound of the Cochin international airport, which was sbut for all arrivals in the afternoon. But after the waters receded at 3 p.m., the airport was reopened.On the night of August 8-9, 22 persons died in various districts of Kerala due to heavy rains and landslides, said a Home Ministry statement. The deaths included 11 in Idukki, five in Malapuram, three in Wayanad, two each in Kannur and Ernakulam one in Kozhikode. Two Class 12 students who ventured out for fishing in the flooded waters near Kochi were swept away. Their bodies were found later.Four teams of of the National Disaster Response Force left from Chennai to Kerala. An inter-ministerial Central team is visiting the flood-ravaged area and Army support is being mobilized from Bengaluru, the statement said.Earlier, Vijayan said the rains had caused extensive damage to life and property across the state. "Since more rains are forecast, as a matter of abundant caution, it has been decided to postpone the upcoming Nehru boat race on the Punnamada lake. The new dates will be announced by the organisers," he said.He said the Central team had agreed to provide all help."Since heavy rains have led to widespread loss and destruction, we call upon all to donate to the Chief Minister's Fund," Vijayan said.Earlier, Power Minister M.M. Mani, who is from Idukki, said the situation in the district was "pretty bad"."The shutters of the Idamalyar dam were opened. We will open a shutter of the Idukki dam also," Mani said.At 12.30 p.m., after a gap of 26 years, one shutter of the Idukki dam was opened as part of a trial run and to assess the water flow. It would be kept open for the night. If the water level does not fall, the other shutters also might be opened on Friday morning.Earlier, Vijayan held an emergency meeting and appointed senior official P.H. Kurian to lead the rescue and relief operations.A special monitoring cell has been opened in the state Secretariat and all the 14 district collectors have been directed to open one monitoring centre in each district.The Southern Naval Command has sent four diving teams and a Sea King helicopter while another aircraft is flying out the NDRF members from Kozhikode to Wayanad to evacuate the stranded people.