The public has access to a range of mobile applications (apps) for disasters.However,there has been limited academic research conducted on disaster apps and how the public perceives their usability.This study explores end-users\' perceptions of the usability of disaster apps.It proposes a conceptual framework based on insights gathered from thematically analyzing online reviews.The study identifies new usability concerns particular to disas-ter apps\' use:(1) content relevance depends on the app\'s purpose and the proximate significance of the information to the hazard event\'s time and location;(2) app depend-ability affects users\' perceptions of usability due to the life-safety association of disaster apps;(3) users perceive advertisements to contribute to their cognitive load;(4)users expect apps to work efficiently without unnecessary consumption of critical phone resources;(5) appropriate audio interface can improve usability,as sounds can boost an app\'s alerting aspect;and,finally (6) in-app browsing may potentially enhance users\' impression of the structure of a disaster app.As a result,this study argues for focussed research and development on public-facing disaster apps.Future research should consider the conceptual framework and concerns presented in this study when building design guidelines and theories for disaster apps.