A very severe cyclone, nicknamed 'Sidr', is fast moving towards the West Bengal-Bangladesh coast and is likely to lash the coast at midnight at a speed of 180-200 km per hour.
The storm was currently lying 500 kms off Kolkata and racing fast towards the state and gathering momentum.
Regional Met office Director G C Debnath told PTI that the cyclone was intensifying and moving fast towards the West Bengal coast gathering momentum.
The weather office has alerted the state administration to the possibility of severe damages in the coastal areas.
"The state administration had been asked to shift the people of the coastal areas to safer locations," Debnath said.
Port authorities have been asked to hoist danger signal No: 10.
The cyclone may affect the five coastal districts, including South and North 24 Parganas and East Midnapur, besides, Kolkata city.
The civic authorities have set up a crisis management group, West Bengal Chief Secretary P R Ray had said adding that alert had already been issued.
Debnath said alert warning to Sagar Island had already been issued.
Fishermen have been advised not to venture into the sea for fishing and to stay alert.
Already, high tidal waves reaching up to a height of three metres were reported in the coastal areas of north Chennai, triggering panic among the fishing community, while the weather office said the phenomenon was due to the severe cyclonic storm formed over the Bay of Bengal.
The cyclonic storm is also expected to trigger extremely heavy rainfall coupled with high speed gale reaching 60 to 90 kmph over North Orissa, official sources said.
In Chennai, as many as 10 huts at Appar Nagar, a fishing hamlet at Tiruvottiyur, were washed away by surging waves, while sea water entered about 200 houses, forcing residents to flee for safety.
Nearly 14 fishing villages in Ennore, Tiruvottiyur, Kasimedu and Ernavur areas had been affected by the tidal waves. Fishermen stayed away from venturing into sea in view of the adverse weather condition.
Fishermensaid they had not seen such ferocious waves in the last eight years. "Not even when the tsunami struck in 2004," they added.
StateFisheries Minister K P Swamy, RDO Sangeetha and other officials rushed to the spot and studied the situation.
WeatherOffice sources said alerts had been received from floating stations of the National Institute of Ocean Technology about high tidal waves due to the cyclonic storm brewing over the Bay and heading towards the north.
Rainor thundershower is likely to occur at many places with heavy falls at isolated places over South Orissa during the same period, it said.
Underits impact, the wind speed was likely to increase as the system approached the coast, while sea condition would be high to very high off North Orissa coast and rough to very rough off South Orissa coast, it said.
Thoughthe system was moving away from Orissa coast, the state government has sounded warning in Balasore, Bhadrak, Mayurbhanj and some other coastal districts close to Sagar Island to remain prepared for rains and gale that might take under its impact.
"Collectorsof these districts were told to monitor water level in different rivers as the rainfall could be unusual," said Revenue Minister Manmohan Samal. He said relief material had already reached places likely to be affected.
The government had already dispatched teams of ODRAF (Orissa Disaster Rapid Action Force)to places where the situation could become worse due to heavy rainfall.
"BothODRAF and medical teams had already reached their destinations," said state Special Relief Commissioner N K Sunadaray.
According to CWC Director Sarat Sahu, the system centered over East Central and adjoining West Central Bay of Bengal, at 0830hrs, was likely to intensify further and move in a northerly direction.
Sahu reiterated that the system was likely to cross West Bengal-Bangladesh coast east of Sagar Island near longitude 89.0degree east.
Hesaid the system was likely to cross Sagar Island by Friday morning.