Why did Noah's wife go to hell according to Quran?

> "God sets forth an example to those who disbelieve: the wife of Noah > and the wife of Lot, they were both under two of Our righteous > servants, but they acted treacherously towards them so they availed > them naught against God, and it was said: Enter both the fire with > those who enter." — Qur'an, Sura 66 (At-Tahrim), ayat 10 Can someone explain to me what exactly did she do that made God angry?