Background
Floods are the most frequent and devastating type of natural disaster, causing unprecedented deaths, diseases, and destruction of property. It accounts for 40% of all natural disasters worldwide. The impact of flooding is exacerbated in developing countries due to poor disaster management structures. The aim to study was to assess the extent, risk, consequence and impact of flood disaster on flood affected communities in Dasench district, Southern Ethiopia, 2021.

Methods
Descriptive cross -sectional study was conducted at flood affected areas in Dasench district from November 25 to December 10, 2021. Data were collected by using mixed approaches through document reviews and in-depth interviews conducted at; District health office, Agriculture office, Education office, Water& energies office; Data were analyzed by MS. Excel; 2010.

Results
Flooding was a common natural disaster in Dasenech district with increased frequency and magnitude during the last three years. The increase were due to excessive or sudden release of water from the nearby hydroelectric power dam (Gibe 3). The flood disasters resulted in displacement of 62,793 population, increased physical injury as well as communicable diseases. Another notable consequence of flooding was crop destruction estimated 95 hectors), damaged infrastructures ( Health center, Health post, animal health post, School, churches, water treatment kit, grained meal, irrigation canal and 367 Private organization in the district. Practice of risk assessment and preparedness was poor in the district.

Conclusion
The district has high risk of flood disasters due to the water released from Gibe 3 hydroelectric dam. Therefore, the district should design a sustainable strategy that addresses water management in nearby dam in order to mitigate and intervain flooding disasters in the future. Also important to design a risk communication and disaster management strategies to improve community awareness and practice during flooding situations.