Winter's Blast

 
Prerequisite(s): Ability to cast 2nd level spells.
 
Benefit: As long as you have a cold spell of 2nd level or higher available to cast, you can create a 15-foot cone-shaped burst of cold. This cone deals ld4 points of cold damage per level of the highest-level cold spell you have available to cast. A successful Reflex save halves the damage. As a secondary benefit, you gain a +1 competence bonus to your caster level when casting cold spells.
 
Source: Complete Mage