In this paper, a review of vision-based natural disaster warning methods is presented. Because natural disaster warning is receiving a lot of attention in recent research, a comprehensive review of various disaster-warning techniques developed in recent years is needed. This paper surveys recent studies on warning systems four different types of natural disaster, i.e., wildfire smoke and flame detection, water level detection for flood prevention, and coastal zone monitoring, using computer vision and pattern-recognition techniques. Finally, we conclude with some thoughts about future research directions.