Interactions between natural events and industrial installations may lead to dangerous phenomena. According to bibliographical research, the industrial sector is often unprepared for these joint natural and technological or Natech events mainly because of the lack of guidelines on how to apply Natech regulations and the lack of information on the dynamics of Natechs. In order to fill the gaps and provide guidance on Natech risk assessment to operators, a systematic risk analysis methodology was developed and resulted firstly in proposing general reference bow-ties that reconfigure accidental scenarios triggered by flood events. The validation of these scenarios was made in the surface treatment sector. Building on these bow-ties, the risk analysis methodology will be completed and a checklist simple to use, along with a list proposing preventive and protective measures, to be used by operators in order to decrease the vulnerability of their industrial facilities to technological accidents triggered by floods will be developed in future work.