It was mentioned back in his 1980's four issue miniseries (Whose most notable claim, much like Darkseid debuting in a Jimmy Olsen comic was that it introduced Oblivion, who would be revealed to be one of the "Big Four" cosmic entities of the MU) than Bobby has two powers, one is the ability to manipulate water vapour and the other to absorb thermal energy from any source (And that can mean that if there isn't enough ambient moisture, he can pull water out of his own body to form the ice, though it was very dangerous to do so for obvious reasons.

It was the "Emma Frost posseses Iceman's body" which seems to have been the first move towards him getting his wider ranger of powers. Because Emma was interesting is neeing what he could do, and wasn't worried about hurting Bobby's body since she didn't plan on being in it long, she demonstrated all sort of new tricks, like reshaping the body, adding things like razor sharp edges to it, and being able to convert entirely into a liquid form for faster travel.

Generally I like the idea he's got more powers than he's shown before, and him doing a "Swamp Thing" style regrowing his body elsewhere I can get behind (Throw in a couple of limitations like needing a sub-zero pathway to travel through) but that "Molecular Inversion teleportation for people other than himself" struck me as an annoyingly random "We need a teleporter... Who can we bafflegab into being one?" situation