The key background event of the storyline that includes Thunder Moon Tussle is the eruption of the Yellowstone super-volcano. This eruption forms the basis for the calendar where the year of the eruption is designated Y+0.
The Yellowstone eruption plays into some of the motivation or emotional state of the characters. It serves as a focal point event where almost everyone relates to it. It has the same affect as the attack on Pearl Harbor or 9/11 had on their respective generations. I recall a lot of the older generations when I was young referring to the attack on Pearl Harbor as a turning point in many of their lives. I've also noticed that many of my peers refer to 9/11 the same way. It may be we are living through another such event with the Covid-19 pandemic.
In this case, you can find references to the Yellowstone super-volcano eruption throughout Thunder Moon Tussle. Nils Carmike and Deputy Miller both refer to Yellowstone as a pivotal event. In his the review of Thunder Moon Tussle, Nathaniel Owolabi makes note of this.
I try to set each of my stories or vignettes on this timeline, though there are some exceptions. The vignette Cold Contact is not on the timeline. The short story Morgan's Road is on the timeline to indicate the year in which Nils Carmike tells the story for the first time. The timeline presented will continuously update with vignettes that give a taste of the background without providing spoilers for any one story.