BACKGROUND: The April 2019 wildfires in Gangwon Province, South Korea forced the evacuation of 1500 individuals and cost more than $100 million in damages, making it the worst wildfire disaster in Korean history. The purpose of this paper was to investigate the mental health effects on survivors following the wildfires. METHODS: Between April and May 2019, outreach psychological support services were delivered to people impacted by the wildfires. Post-disaster psychological responses using a checklist and the Clinical Global Impression Scale-Severity (CGI-S) were evaluated for 206 wildfires survivors. The CGI-S was administered consequently at 1, 3, and 6 months after baseline measurement. RESULTS: Among four response categories, somatic responses (76.2%) were most frequently observed among the wildfire survivors. Specifically, insomnia (59.2%), anxiety (50%), chest tightness (34%), grief (33%), flashbacks (33%), and depression (32.5%) were reported by over 30% of the participants. The mean CGI-S scores were significantly decreased at 1 month (mean score = 1.94; SE = 0.09) compared to baseline (mean score = 2.94; SE = 0.08) and remained at the decreased level until 6 months (mean score = 1.66; SE = 0.11). However, participants with flashbacks showed significantly higher CGI-S scores compared to those without flashback at 6 months. CONCLUSIONS: Wildfire survivors have various post-disaster responses, especially somatic responses. While most participants' mental health improved over time, a few of them may have experienced prolonged psychological distress after 6 months. Flashbacks were particularly associated with continuing distress. These results suggest that the characteristics of responses should be considered in early phase intervention and in follow-up plans for disaster survivors.