Arcane Storm

You create a tear into the very source of magic that sustains spells. Originating from you and traveling no more than 50 feet you unleash this tear to rain down arcane power. You control the rift and determine which 5ft cubes get bombarded within its path. Each bombardment does a minimum of 2d6 force damage and a maximum of 4d6.  The spell is considered expended when 10d6 damage has been allocated and no more than that amount can be allocated without expending a higher level spell slot.  With DM discretion, the caster must choose the path the storm takes quickly lest the DM choose the next square.  Creatures caught within a bombardment may make a Dexterity saving on a successful save they take half as much damage.

Spells at 6th level and higher do an additional 2d6 for each level above 5th.