This study aimed to evaluate mental health factors in individuals affected by the floods in Rio Grande do Sul from May 10 to June 6, 2024. A real-time survey was conducted with 1,552 participants. The Patient Health Questionnaire-9 (PHQ-9), Generalized Anxiety Disorder-7 (GAD-7), and Acute Stress Disorder (ASD) symptom checklist were used to assess mental health outcomes. Sociodemographic factors, trauma exposure, rescue participation, and psychological support were evaluated. Statistical analyses included t-tests, ANOVA, linear regression, and MANCOVA. High rates of depressive and anxious symptoms were found, with over half of the individuals with moderate to severe symptoms reporting no prior history of these conditions. Participants directly affected by the floods, and those with close ones affected, had higher PHQ-9, GAD-7, and ASD scores compared to the unaffected group. Moreover, younger age, female sex, lower family income, participation in rescues, and unmet psychological support needs were correlated with worse mental health outcomes. Individuals who participated in rescues had significantly higher rates of suicide ideation. Notably, psychological support had the largest effect size in mitigating mental health symptoms, regardless of trauma exposure status, when controlled for age, sex, and income according to MANCOVA. The findings highlight the critical role of psychological support in disaster response and the importance of community resilience. Real-time data collection during crises can inform targeted interventions, emphasizing the need for robust mental health services and community support networks. These efforts are essential to reduce long-term psychological morbidity and foster recovery in vulnerable populations.