"Estimating settlements exposure to flood risk: Floods in Myanmar occur during the monsoon months in May/June to September/October and include wide spread flood along the major hydrological network and and flash flood at the small rivers and stream. The main cause of wide spread flood is heavy rainfall striking at the head water regime for considerable period (1 to 3 days), the flood wave forming at the head water started to move downward and causing flood along the river up to the deltaic area. The flash flood is caused by heavy rainfall fell on the source and the flood wave move downward swiftly. Observation shows that the percentage of occurrence of floods (exceeding danger level) in medium and large rivers of Myanmar are 6% in June, 23% in July, 49% in August, 14% in September and 8% in October..."