Snowcaster

Your magical power grows as the shard's icy influence spreads ever deeper into your being. You gain the basic spellcasting benefits. Each time you gain a spell slot of a new level from this archetype, add a spell of the appropriate spell rank (including heightened versions of lower-rank spells) to your repertoire, either a common spell of the arcane tradition that has the cold trait or another cold spell you have access to.