In the Silmarillion, at the end of the First Age and after the War of Wrath, the cities of Nogrod and Belegost in the Blue Mountains "were utterly destroyed"
Did this include the populations of Dwarves, or were they evacuated first somehow?
Science Fiction & Fantasy Stack Exchange is a question and answer site for science fiction and fantasy enthusiasts. It only takes a minute to sign up.Sign up to join this community
There were likely some casualties, but at least some of the inhabitants made their way to Moria (emphasis mine):
After the end of the First Age the power and wealth of Khazad-dûm was much increased; for it was enriched by many people and much lore and craft when the ancient cities of Nogrod and Belegost in the Blue Mountains were ruined at the breaking of Thangorodrim.
Return of the King Appendix A: "Annals of the Kings and Rulers" III "Durin's Folk"
According to Appendix B, this was a little ways into the Second Age:
c. 40 Many Dwarves leaving their old cities in Ered Luin1 go to Moria and swell its numbers.
Return of the King Appendix B: "The Tale of Years" (i) The Second Age
So it would appear that the destruction of the two cities wasn't quite as "utter" as all that. What exactly they were doing for those 40ish years, however, is unrecorded.
1 The Blue Mountains; both Nogrod and Belegost were founded there