Quote Originally Posted by Crake View Post
Available to cast is a subset of able to cast.

Anything available to cast is necessarily something you are able to cast. Thus, if a heightened 5th level fireball is considered a 5th level fire spell available to cast, it must necessarily be a 5th level spell you are able to cast, else it would not qualify as one available to cast.
Well, Snowcasting definitively does not increase the level of spell you have available to cast, nor does Sanctum Spell or Earth Spell, so if this is the case, then it only reinforces my initial opinion from earlier in the thread that it was sloppy to use them for your leapfrogging build when you could have used Eldritch Corruption.