You summon the cataclysmic powers of fire and ice in a 30-foot-radius sphere at a point within range.

When you cast this spell and at the start of each of your turns for the spell's duration, choose either fire or cold. Each creature in the affected area must make either a Dexterity saving throw (for fire) or a Constitution saving throw (for cold) or take 3d10 damage of the selected type.

Any creature that takes both fire and cold damage from this spell takes 3d10 necrotic damage at the start of each of its turn for the duration of this spell.

At Higher Levels. When you cast this spell using a spell slot of 5th level or higher, increase the fire, cold, and necrotic damage dealt by 1d10 for each spell slot level above 4th.