The nexus between migration and Water Induced Disaster (WID) has commonly been referred in the previous research. In particular, previous studies often describe migration as a coping strategy for the climate and water induced disaster. Yet, very limited studies have been conducted in the past which reveals migration as a triggering factor to promote disaster events in a certain location. Considering this research gap, this study aims to assess the conditions under which internal and external migration promotes disaster events. Employing qualitative research method and taking the East Rapti River Basin located in Chitwan and Makhwanpur districts of Nepal as a case, this study indicates that internal migration towards the study area upstretched after mid 1990’s resulted the increasing tendency of WID in the region, mainly due to over exploitation of resources and change in land use practices in the Chure region and Terai. Likewise, unplanned urbanization and haphazard land use practices that begun after 2000 due to the flow of remittance from external migration to these areas has further contributed to increase in incidences related to WID as well as vulnerability of the residents especially women, children, and left behind population of these areas.