system
Given the following post, respond as if you're commenting on Reddit:
human
How were forest fires contained 150 years ago, especially in remote areas like the west?

It seems like if there was a fire back then in say, what is now Idaho, it would burn down the entire western US and there would be no way to stop it.
gpt
Well, in short they weren't contained. Only natural obstacles like cliffs, rivers, sparse vegetation, wetlands, rain, and the fact that the wind doesn't blow in all four directions at once, limited the forest fires. 

That would be the case today as well, but we have put suburbs and towns everywhere so we simply can't let fires go the way the wind blows them anymore. Fires weren't a big problem back then because there simply wasn't that much human property in the way of the fires. In 1850 there was only about 23 million people in the US. If you took a thousand long steps in one direction, and then turned right 90 degrees and went a thousand more steps, and then did it twice more, the square area you would have walked around would be shared by you and just one more person in 1850. Today you will share it with 30 people. So any random area there's a fire, its 1600% more property that the fire will destroy, that is why fires are a problem now, not then. 

PS: Though it should be noted that towns did burn to the ground back then because of forest fires. It was just far less likely to happen because towns were smaller, fewer and farther apart. 

PPS: Oh, and people tended to use the trees near a town to build the town, so there was usually open barren area around towns to protect against forest fires. At worst some crops around the town, that they could burn away before the forest fire arrived. The forest fire brings extra wind because of the movement of the hot air upwards, so if you do a small burning of some fields of crops there's little of that and the wind doesn't make the fires jump across the road to your buildings. Whereas when the forest fire arrives the wind gusts will make the fire skip from the crops to the buildings across the road. They did not normally keep trees as pets close by their suburb for it to look nice and be a huge forest-fire hazard. But we do today.