How about the same feat for Pathfinder?
Winter Witch (Metamagic)
You ARE the cold of winter when in your element.
Benefit: When you cast a spell with the cold descriptor and are standing in snow, you increase all level dependent effects by one up to one higher then you level. You may do this a number of times per day equal to your spell casting statistic bonus.
Level Increase: +1 (a rime spell uses up a spell slot one level higher than the spell’s actual level.)