Ice Storm Spell
D&D Ice Storm Spell Description: Great magical hailstones pound down for 1 full round, dealing 3d6 points of bludgeoning damage and 2d6 points of cold damage to every creature in the area. A -4 penalty applies to each Listen check made within the ice storm's effect, and all land movement within its area is at half speed. At the end of the duration, the hail disappears, leaving no aftereffects (other than the damage dealt).
More on the Dungeons & Dragons Ice Storm Spell
This is one of my favorite spells to use in the gaming worlds. I have two mages that walk around the worlds adventuring. Their favorite first attack is a fireball followed with a ice storm. I have found that these two spells fired in the same melee round really causes great havoc.