Perhaps he is just "surging" as a percentage of Democrat voters. People are deserting the Democrat Party by the gazillions, leaving only the twinkies and other freaks who can't possibly fit in with any group of humans.
“Whats Behind Buttigiegs Iowa Surge?”
It remains yet to be seen what happens, but I’ll never forget 2004 when Howard Dean was all the rage, and he had Iowa in the bag. He failed miserably. Most of the time I think it’s just pollsters/media types pushing who they want.