Amoth is a god of justice and mercy. He is dead, slain centuries ago by several demon lords during a battle involving multiple planes. Something significant happened here.
We learn in Session 036 that the city actually disappeared after a massacre during The War. In Session 039 we learned that the land of this city was bought up by the hobgoblin Ilxavar and was being studied by he and his contingent of goblins. We arrive Session 040.
The first thing we realize is that the city was once quite large. Rivaling the size of Apamea, it may have been the largest city in the north. All that is left at this point is ruins. There is a clear circular radius outside of the city that is where the effects of what happened ends, marked by the snow being discolored to a grey color, that grows darker as it grows towards the center of the city, where the blast seems to have originated (at the actual origin there is no more snow).
Of note, Arythas and Dia noticed that there was some sort of anti-divinity type energy on the place, dampening their connection to their respective deities.
It is clear that there was once powerful magic in this area, but it is only traces now and otherwise inert. Dotted along the walls that are left there are still the shadows of people (blast shadows) that were caught in the blast. At the epicenter of the explosion, however, are some corpses, some of which we realize are actually ghouls.
Dia’s friend Neminna recalls her father speaking about the fact that they were fighting with something that ate corpses.