Azure Blast

A beam of Azure flame forming a line 150 feet long and 5 feet wide blasts out from you in a direction you choose. Each creature in the line must make a Dexterity saving throw. A creature takes 10d6 Fire damage on a failed save and then 1D6 each turn as they are are set on fire till they remove the flames. half as much damage on a successful save and they are not set on fire. 
The flame ignites flammable objects in the area that aren't being worn or carried.

At Higher Levels. When you cast this spell using a spell slot of 6th level or higher, the damage increases by 1d6 for each slot level above 5th.