User blog comment:FairyRaven/Fairy Tail Chapter 351: Eternal Fire, Review and Commentary/@comment-7418318-20130912130415

So both the flame and ice disappeared together?

That actually makes sense, if you think about it. If you put water and fire together, you'll get steam. If the volume/intensity of both is just the right balance, there's neither (liquid) water nor any fire left.

If Gray only "pulled out" the magic that sustained the ice so far, but left the actual ice intact, it would probably return the flames to being hot and thus the remaining ordinary ice is turned into water and then into steam.

And in the process the flames also disappeared either because they lost too much heat or because the source that used to sustain them is still frozen, or otherwise unable to sustain them.