Minecraft wiki entry for Thunderstorm_survival, associated text: If you see a fire, put it out as quickly as possible. If you do not have a bucket, you can break the fire simply by punching the fire's hitbox. If it is not put out, it could spread and, although there is a limit to how far it can spread individually, it is still undesirable, especially if near the player. If you don't have a water bucket to put out the fire, and it's too big to break with your fist, just get away, and the fire should eventually stop.