Why does it mention the elevation?
Malbim: Because their hearts were elevated (haughty), they did abominations in front of Me.
Why is there a Yud in "va'Tigbehenah"? Is it plural?
Rashi: Yes, it refers to [Sedom] and its villages 1 , like it says in Iyov (28:5) "Eretz Mimenah Yetzei Lachem." They said, we will stop people from passing through our land - they come only to cause loss.
Radak #1: The Yud is merely for similarity to va'Ta'asenah.
Radak #3: It refers to Sedom and Shomron 2 .
What is the meaning of "va'Asir Es'hen"?
Radak #1: I totally destroyed the nation and the cities (Sedom and its villages). I overturned them; they will not be settled.
Radak #2: I exiled Shomron, and destroyed Sedom.
Why does it say "Ka'asher Ra'isi"?
Rashi: When I saw their way, like it says about Sedom "Eradah Na v'Er'eh..." (Bereishis 18:21).
Radak: It seemed to Me that this was the proper judgment for them.
Malbim: I sent My angels to see 1 , "va'Ta'asenah To'evah" - they demanded to sodomize my messengers. Homosexuality is called To'evah (Vayikra 18:22).
I.e. he sent angels to Sedom; Lot tried to advocate for his city (Rashi Bereishis 19:12, from Bereishis Rabah 26:5). Hashem knows everything; He sent angels to see, to teach that a judge must gather information before deciding. (PF)