Rivers in the coastal south are swelling as a low-pressure system over the Bay of Bengal triggered a tidal surge.
At least 15 villages have been inundated in Jhalakathi as three rivers flowed five feet above the normal level on Wednesday.
The water levels of the Sugandha, Bishkhali and Halta rivers are currently around 19cm above the danger level, said Md Raqib Hossain, a sub-divisional engineer at Bangladesh Water Development Board's Jalakathi wing.
Some 10 villages in the coastal areas of Kathalia Upazila were hit by flooding on Wednesday. Several government offices in the Sadar Upazila are submerged in knee-deep water, according to Md Faruk Hossain, secretary of citizens' rights group Shushashoner Jonno Nagorik.
"Residents of the region have to suffer the most during natural disasters as there is no embankment in the 31-km stretch from Amua to Jangalia."
Five other villages in the Sadar, Nalchhiti and Rajapur upazilas have been inundated as the Sugandha and Bishkhali rivers burst their banks. Many houses in the low-lying areas of the district have also been flooded.
FLOODS TO SWEEP THE SOUTH COAST
In its latest weather bulletin, the Met Office has advised the maritime ports in Chattogram, Cox's Bazar, Mongla and Payra to hoist the local cautionary signal No. 3.
A depression over the coast of Odisha in India weakened into a well-marked low and is tracking northwestward, it said.
The squalls generated by the low has triggered a tidal surge that is around 4 feet above the normal level, said meteorologist Md Omar Faruq.
The low-lying areas of Satkhira, Khulna, Bagerhat, Jhalakathi, Bhola, Barishal, Noakhali, Chattogram and Cox's Bazar are likely to be inundated by the rising tide.
All fishing boats and trawlers have been advised to remain close to the coast and proceed with caution.