, Aug. 12 -- Vast swathes of countryside along Bangladesh's all three major river systems - Ganges, Brahmaputra and Meghna - face the threat of being flooded over the next three days as extremely heavy rain begins in the upstream covering parts of Nepal, Bhutan and India.

Thousands of people in low-lying remote areas along the Padma got stranded in flood water on Tuesday with authorities shutting down over a dozen schools amid the Padma rapidly swelling and India issuing red alert for its states upstream adjacent to Bangladesh.

The upstream Indian states and parts of Nepal and Bhutan where extremely heavy rainfall is occurring comprises the world's wettest place and one of the largest mountain ranges.

An event of extremely heavy rainfa...