When hydrological disasters occur in local rural communities, the demand for health services increases, especially in primary healthcare.1 Health services are essential in the response to a disaster where nurses all over the world play a significant role.

To identify nurses’ competencies when responding to disasters caused by floods in the rural area.

A descriptive, exploratory, and qualitative study was developed. The Critical Incidents Technique was adopted. Twenty public health nurses who worked during the flood season in the years of 2014 and 2015 in a rural area in Southern Brazil were interviewed. Critical incidents and requirements identified in the empirical data gave rise to the development of the competencies.

Thirty competencies were identified and classified in the following domains: leadership and management, teamwork, health care, community-oriented, communication, psychological support, health surveillance, and education.

Although the competencies could be related to the established international competencies for the nurse in disasters, some were described only in this study. They can contribute to the education and practice of nurses in primary health care, strengthening its capacity to face disaster situations by flood in the rural area.