Storm Spell Damage Comparison
Storm PP Total Area Avg Avg/Pwr
Icestorm 6-26 x 3 = 18-78 96 45 3
Firestorm 12-30 x 3 = 36-90 128 63 3.706
Blizzard 10-32 x 3 = 30-96 64 63 3.316
White Death 7-25 x 5 = 35-125 64 80 3.478
Maelstrom 12-50 x 3 = 36-150 128 93 3.72
Manastorm 13-190   128 101.5 3.759
Uttervoid 1-60   128 30.5 1.452

All damage values are for direct hits.
Testing suggests that "splash" is 1/2 direct damage.

PP = Per Projectile - the damage inflicted per "hit"
Avg = average damage inflicted assuming all projectiles hit
Avg/Pwr = average damage inflicted per point of power used to cast

All values expressed exactly if possible, or to 3 decimal places