There are four different versions of Big Thunder: One at Disneyland, one in the Magic Kingdom at Walt Disney World, one at Disneyland Paris, and one at Tokyo Disneyland. With that said, the story of Disneyland’s Big Thunder Mountain may differ from that of the other park’s attractions. I know for a fact that Disneyland Paris’s Big Thunder is set in their version of Frontierland which has a completely different story and connects with their version of The Haunted Mansion!
The setting of Big Thunder is in the city of Rainbow Ridge, a small town that grew quickly when gold was found within Big Thunder Mountain. You can see the theming of Frontierland hint towards this town in mulitple places, especially back on Big Thunder Trail.
Once the gold was found, miners started using pick axes and other hand tools to get to the gold. Little did the townspeople or workers know, Big Thunder Mountain is actually the location of an ancient Indian burial ground, and the destruction of the mountain by the miners displeased the spirits.
The miners then decided that the hand tools weren’t working well enough, and that they could get rich faster with a different method: explosives. Thus, the miners started blowing up sections of the mountain. This was too much for the Indian ancestors, who decided to fight back against the miners and townsfolk.
Accidents started occurring at the Big Thunder Mountain Mining Co., with explosives blowing up on their own and mine trains running all by themselves. Big Thunder is the only attraction that has ‘trains’ that aren’t driven by a person.
After mining became too dangerous because of the spirit’s anger, the mining company and the town of Rainbow Ridge was abandoned. That’s why there are animals crawling all over Big Thunder, because there are no people to scare them away!
Two mountains visible at night!
Growing up in Los Angeles in the 70s/80s we visited Disneyland on a regular basis and often after school, before "Annual Passes".