Trump did surprisingly well in Iowa actually. In fact his coverage was a lot better than predicted. He was expected to do well in the south and southwest but his coverage was surprisingly widespread as was Cruz's. The real issue is Rubio winning a whopping 5 counties.
As far as Carson is concerned, he only led in 3 counties very early on and Trump won those counties.
Two of the counties Rubio won are the most populous in the state.
A product of paid media buys and MSM fluffing.