Blizzard

You create an ice mayhem around you, that pierces and freezes everyone but you in a 15 foot radius circle centered on you. Each creature in range must suceed on a constitution saving throw or suffer 5d8 cold damage and have their speed be reduced by 15 until the end of their next turn. A creature that succeeded this saving throw takes half the damage and their speed is not reduced.

Casting this spell with a higher level spell slot adds 2d8 to the damage for each spell slot higher than level 3 used to cast this spell.