( وَأَمْطَرْنَا عَلَيْهِم مَّطَرًا) (And We rained upon them a rain [of stones]): It is definitely not an ordinary rain but one composed of hard clay stones. Allah (swt) explains to us what kind of rain it was in another Surah:

 فَلَمَّا جَاءَ أَمْرُنَا جَعَلْنَا عَالِيَهَا سَافِلَهَا وَأَمْطَرْنَا عَلَيْهَا حِجَارَةً مِّن سِجِّيلٍ مَّنضُودٍ

(So when Our command came, We made the highest part [of the city] its lowest and rained upon them stones of layered hard clay, [which were]) (Hud: 82)

Allah (swt) turned the whole village upside down and rained upon them stones of hard clay.

( فَانظُرْ كَيْفَ كَانَ عَاقِبَةُ الْمُجْرِمِينَ) (Then see how was the end of the criminals): The punishment of those people who committed such an abomination should be a lesson to be learned and contemplated upon.