Game environments are not built with a ruler and some tape, they are built with imagination and an understanding of what is needed to make the game environment. If you take the time to learn about what you will need to do before you being the process, it will make for better results in less time with less work.
PCs camp for the night in a dry pine forest. Fire skill of the person that made it is usually pretty good, but during the first watch the unexpected happens: a spark lights the surrounding woods and a brush fire quickly starts. Be quick or it could turn into a disaster that could affect the entire region.