That sounds right too. It happens quick. 90-plus temps, high humidity, stagnant water. Even when stranded people were outside in the elements the main reason they suffered so much was because of the climate. If you've not experienced it, it's difficult to describe. Imagine trying to breath through a thick, woolen blanket... imagine you are soaking wet at the same time. Now... also imagine being constantly bit by mosquitos. I moved my wife down there early in our marriage and I'm still hearing about it.
I hated it when I lived there. Every time I came out of an air conditioned building my glasses would fog up. And bugs! Roaches the size of volkswagens.
Well, then the hurricane people that were sent to Houston will feel right at home...because what you described is exactly how Houston feels in the summer...blech!