329mm of rain in a day as landslides and floods kill 54 in seven districts

Days of heavy rain from the first week of July 2026, with hill run-off and landslides, had killed 54 people across seven districts of Bangladesh by 20 July, BBC Bangla reported that day. Chattogram division, and its hill districts above all, was worst hit, with flash floods in low-lying parts of Chattogram. The Bangladesh Meteorological Department said 329 millimetres of rain was recorded in Chattogram in a single day that month, the highest in many years.

Prothom Alo reported on 9 July that landslides had killed 22 people over the previous three days, including 10 in Cox's Bazar in a single night, eight of them in the Rohingya refugee camps.

The Ministry of Disaster Management and Relief's report of 11 July named the seven affected districts as Khagrachhari, Rangamati, Bandarban, Cox's Bazar, Chattogram, Moulvibazar and Habiganj. By then 44 people had died, 39 were injured and 1,022,963 were affected. By 20 July, BBC Bangla counted 54 dead.

Bangladesh receives 71 percent of its annual rainfall in the June to September monsoon. July is the wettest month and the one when landslide risk peaks.

Meteorologist Bazlur Rashid told BBC Bangla that the monsoon depression moved due west, very close to the Bangladeshi coast, so the rain fell mainly on Chattogram division, and the rest on Barishal division, rather than across the country. "Because there are hills to the east of Chattogram, the moist air could not cross them easily," he said. "So that air stayed over the same area for several days and produced continuous heavy rain."

According to the Met office, the highest July rainfall since independence was 407 millimetres, in 1983. Rashid said the monsoon itself was changing: June 2026 had brought about 30 percent less rain than normal, and when the early season falls short, very heavy rain tends to come later in short bursts. He added that the effect of a strong El Niño, a natural warming of the Pacific that shifts rainfall around the world, also had to be considered.

One day of heavy rain rarely brings a large landslide; days of rain soak the soil and weaken slopes. Rashid said that since the Rohingya crisis, hills in and around Cox's Bazar had been cut on a large scale, so landslides now happen with comparatively less rain and the loss of natural vegetation had loosened the soil.

Engineer Delwar Hossain Majumder, former chairman of the Chattogram centre of the Institution of Engineers, Bangladesh (IEB), said Chattogram's hills are only about 2.5 million years old, sandy and prone to erosion by nature, and only a third of Chattogram city's hills survive. He blamed unregulated settlement at the foot of the hills, hill cutting and the loss of natural vegetation. Five kathas of land can be worth five crore taka, he said, yet the fine for cutting a hill is one lakh taka, so it should be raised.

On 11 June 2007, landslides at six places in Chattogram, including Motijharna in the Lalkhan Bazar area, killed 127 people after 425 millimetres of rain fell in 24 hours. On 12 June 2017, heavy rain from a depression over the Bay of Bengal set off landslides in Rangamati, Chattogram and Bandarban; BBC Bangla puts that year's toll at more than 160. Research by Dr Md Ashraful Islam, associate professor of geology at the University of Dhaka, records more deaths: 13 in Chattogram in 2008, 66 in Cox's Bazar in 2010, 17 in Chattogram in 2011, seven in Chattogram in 2015 and two in Cox's Bazar in 2019.

Experts rank the hills of Chattogram, Cox's Bazar, Bandarban, Rangamati and Khagrachhari as the most landslide-prone in the country, hillside settlements in Chattogram city most of all. Rashid said the administration must be told in advance which hills are dangerous, and the hills left as they are. He thought a major landslide unlikely soon unless heavy rain returned. Ashraful Islam said Chattogram's hills were becoming more dangerous by the day, but the scale of the next landslide could not be predicted.

Photo: Ferdous / Wikimedia Commons (CC BY-SA 3.0)

Sources: BBC Bangla, Prothom Alo, Wikipedia