Book Earthside — Dennis E. Taylor

The Yellowstone super-eruption has put an end to modern civilization. As cities and countries continue to fall, the colony of Rivendell in the alternate Earth known as Outland looks more and more like the only real hope for humanity. But life in Rivendell isn’t getting any simpler, either. Bill and Kevin continue to discover new worlds; the population continues to rise; winter is approaching; and everyone has their own opinion about how things should be run.

Then, a garbled plea for help from Omaha sends most of the security forces back Earthside to investigate, leaving Outland’s police force understaffed just as a large group of refugees arrives with its own ideas and power structure. With threats from both inside and outside, will the colony even survive until spring?