Cyclone Mahasen is likely to hit the coastal areas of Bangladesh today.
The tropical storm may cross the Chittagong coast around midday, bringing heavy rain and eight to 10 feet high tidal waves in its wake, according to a Bangladesh Meteorological Department (BMD) bulletin issued last night.
The authorities have raised the danger level to seven, on a scale of 1 to 11, for Chittagong and Cox's Bazar ports.
Although not very strong, Mahasen is a very large storm, said Nasa in its website, adding that the storm would cause high tide and heavy rainfall.
Talking to The Daily Star, BMD Director Shah Alam could not predict whether Mahasen would be as severe as the 2007 super cyclone Sidr, but said it might have a maximum wind speed of 100km per hour during land fall.
The maximum wind speed at the storm centre is expected to be between 62 and 90kmph. The sea will remain rough near the storm centre.
The 2007 Sidr and the 1991 Chittagong cyclones were category-5 super cyclones, having up to 260kmph wind speed. The 1970 Bhola cyclone was a category-3 tropical cyclone with maximum 205kmph wind speed, while the 2009 Aila was a category-1 cyclone with maximum 110kmph wind speed.
At midnight last night, the BMD bulletin said, Mahasen was lying in the West Central Bay -- some 555km southwest of Chittagong Port, 500km southwest of Cox's Bazar Port and 445km south-southwest of Mongla Port.
The storm may cross the region between Patuakhali and Teknaf coast near Chittagong by this morning, but squally wind started to affect the coastal region last night.
The danger level is below seven in the coastal districts of Chittagong, Cox's Bazar, Noakhali, Laxmipur, Feni, Chandpur, Bhola, Barguna, Patuakhali, Barisal and the offshore islands of these districts.
The Mongla Port authorities have been advised to keep its danger level at 5, with the same being applied to Pirojpur, Jhalakathi, Bagerhat, Khulna and Satkhira.
Under the influence of the storm, the low-lying areas of Cox's Bazar, Chittagong, Noakhali, Laxmipur, Feni, Chandpur, Barguna, Bhola, Patuakhali, Barisal, Pirojpur, Jhalakathi, Bagerhat, Khulna, Satkhira and the offshore lands of these districts are likely to be inundated by a surge eight to 10 feet higher than the normal tide.
Due to heavy rainfall, landslides may occur at places over the hilly regions of Chittagong division, the Met office warned.
All fishing boats, trawlers and marine vessels over the North Bay have been advised to remain in safer places till further notice.
The coastal districts of Cox's Bazar, Chittagong, Noakhali, Laxmipur, Feni, Chandpur, Barguna, Patuakhali, Barisal, Bhola, Pirojpur and their offshore islands are likely to experience wind speed of up to 90-100kmph with heavy to very heavy rain during the storm.
Jhalakathi, Bagerhat, Khulna, Satkhira and their offshore islands are likely to experience wind speed of up to 80-90kmph with heavy to heavy rain.
Meanwhile, officials of Bangladesh Inland Water Transport Authority and launch owners association said no long-route launches left the Sadarghat terminal for coastal districts yesterday.
Till 8:30pm, train communication was normal, while some private bus companies suspended their operations from Dhaka to different coastal districts.
An integrated control and monitoring cell has been set up at the Armed Forces Division to provide information and other necessary support round the clock, said a statement of Inter Services Public Relations. Helpline numbers are 9834358, 9834399 and 01769014314.
Besides, 22 vessels of Bangladesh Navy have been kept on alert for relief distribution and rescue operations.