1)
What exactly did HaSh-m do to the four towns?
1.
Rashi: They were all on one rock. HaSh-m turned it upside-down. 1
2.
Seforno: He turned them into sulfur and fire (the substances that had destroyed them).
1
Gur Aryeh: The verse writes "overturned" (va'Yahafoch), rather than 'destroyed' (va'Yachariv). This implies literally overturning, not each city individually, but all four at once.
