The Lord has many ways that he uses to destroy the wicked, such as earthquakes, floods, war, famine, floods and famine, but he reserves destruction by fire for the most wicked, so that there is "neither root nor branch" left (3 Nephi 25:1).
Here's some other cases where wicked people are destroyed by fire. In each case, there are no righteous remaining at all.
Sodom and Gomorrah
See Genesis 19:24-25,27-28.
Again, the destruction is complete, "all the plain, and all the inhabitants of the cities, and that which grew upon the ground."
There were lots of cities burned by fire: Zarahemla, Laman, Josh, Gad and Kishkumen.
The story is in 3 Nephi 9:3,9-11.
Here are the reasons for the city of Jacobugath specifically:
Malachi prophesied that at the Second Coming, all the wicked shall be burnt. See Malachi 4:1.