And then there's this looming supervolcano:

https://www.independent.co.uk/news/science/risk-of-supervolcano-eruption-big-enough-to-...

Even though the article says that this could erupt without any warnings, there has been a recent uptick in activity in the area.

A couple more leaks regarding fairly recent earthquake swarms in the area:

http://www.newsweek.com/yellowstone-supervolcano-earthquake-swarm-eruption-risk-627189

https://news.nationalgeographic.com/2018/02/yellowstone-national-park-supervolcano-eart...