Most of the time when I’m drawing environmental maps or locations they don't necessarily have a story, I don't tend to create locations like these for a specific campaign or adventure. Instead they tend to be made for many different purposes so that people can use them in their own homebrew worlds.
That being said, this map definitely does have a story behind it, you can use it for whatever you want, but what I imagined gave the area a little bit more detail!
“For some unknown reason the earth and rock in a remote mountain valley began to rip itself apart, tearing through the world and bringing forth a host of deadly creatures and noxious gases. Destructive earthquakes rippled throughout the region as well, causing untold chaos to settlements hundreds of miles away from the newly emerging rift. Unfortunately this event was also foreseen by a cabal of warlocks that seized the opportunity to study the rift and use its power for their own ends. When they arrived however, they quickly realized that the rift was growing larger than they could safely control. They had no choice but to try and stop the expansion while still keeping it stable enough to use. They fashioned a number of magical chains across the growing chasm and a created a rift stabilizing device to expel any excess energy that builds up below. The warlocks were rewarded for the their efforts with a constant supply of magical energy and have now grown so powerful they threaten nearby villages and towns with their dark magic and summoning abilities.”
This map was also made a little differently that normal, I placed extra bits next to a normal A4 piece of paper, making it larger while still allowing me to scan and move it around to draw and ink. :)