Bangladesh: Adverse weather forecast across most of the country through at least June 26

Severe weather is forecast across most of Bangladesh through at least June 26. Heavy rainfall has been affecting much of the country in recent days amid the ongoing monsoon season; the Bangladesh Meteorological Department has forecast further downpours in most areas over the coming days. As of June 19, the department has issued a heavy rainfall warning over Chattogram, Mymensingh, Rangpur, and Sylhet divisions for 72 hours commencing 09:00 June 19. Light-to-moderate rainfall and isolated thunderstorms are forecast across the rest of Bangladesh through at least June 26. Strong winds are also expected in coastal areas: a marine wind warning has been issued advising the ports of Chittagong, Cox's Bazar, Mongla, and Payra to hoist local cautionary signal number three (out of ten). Heavy downpours may trigger flooding in low-lying areas and landslides on unstable slopes. Strong winds may cause property damage and power outages.

Heavy rainfall in recent days has led to flooding and associated disruptions in parts of the country, with Sylhet Division worst affected. Many rivers across northeastern Bangladesh are overflowing due to the incessant rainfall and further adverse weather over the coming days will likely exacerbate the flood situation. Flooding has submerged many homes and roads in Sunamganj and Sylhet districts of Sylhet Division, leaving thousands of people displaced and hundreds of thousands of others stranded. Power outages are also impacting parts of the affected regions. In southeastern Bangladesh, authorities have reported at least nine fatalities after heavy rainfall caused multiple landslides in refugee camps in Cox's Bazar District in Chattogram Division.

Sustained heavy rainfall could trigger flooding in low-lying communities near rivers, streams, and creeks. Urban flooding is also possible in developed areas with easily overwhelmed or a lack of stormwater drainage systems. Sites located downstream from large reservoirs or rivers may be subject to flash flooding after relatively short periods of intense rainfall. Landslides are possible in hilly or mountainous areas, especially where heavy rainfall has saturated the soil. Disruptions to electricity and telecommunications services are possible where significant flooding or landslides impact utility networks.

Floodwaters and debris flows could render some bridges, rail networks, or roadways impassable, impacting overland travel around affected areas. Ponding on road surfaces could cause hazardous driving conditions on regional highways. Authorities could temporarily close some low-lying routes that become inundated by floodwaters.

Severe weather could also trigger flight delays and cancellations at airports across the affected region. Authorities may temporarily suspend port operations along the Bay of Bengal coast if strong winds trigger hazardous sea conditions, impacting freight and passenger maritime traffic.

Flooding could block regional rail lines; freight and passenger train delays and cancellations are likely in areas that see heavy rainfall and potential track inundation. Localized business disruptions may occur in low-lying areas; some businesses might not operate at full capacity because of flood damage to facilities, possible evacuations, and some employees' inability to reach work sites.

Flooding could heighten the threat of disease outbreaks. Backflow from drains mixed with floodwaters can become trapped in open areas when inundations recede. These stagnant pools often become a breeding ground for mosquitoes and bacteria, increasing the incidence of insect- and water-borne diseases. Exposure to contaminated water from inundated industrial sites, sewer systems, and septic tanks also poses a significant health threat.