I'll show you an overpowered 4th level damage spell...

1. Use the Snowcasting metamagic feat to give Locate City the [Cold] descriptor.

2. the Flash Frost Spell metamagic feat to cause the spell to deal 2 points of cold damage per spell level (In this case, 1, so 2 points of damage).

3. Use the Energy Substitution (Electricity) to cause the [Cold] descriptor to change to the [Electricity] descriptor. This may or may not change the 2 points of cold damage to Electricity damage, but it doesn't matter.

4. Apply the Born of Three Thunders metamagic feat to this monster of a spell. All it requires is that the spell has the electricity descriptor or the sonic descriptor and deals hit point damage. This causes half of the spell's damage to be electricity damage and half sonic damage, for 1 point of damage each. More importantly, it then gives the targets a Fortitude save in order to avoid being stunned for one round. If they fail this save, they then get a Reflex save to avoid being knocked prone. Both of these saves are at the same save DC as the original spell was.

5. Note that this horrible mishmash of metamagic feats now has a Reflex save.

6. Apply the Explosive Spell metamagic feat to this thing. On a failed Reflex save, they're ejected to the edge of the spell, taking 1d6 damage for every 10' they traveled.

7. Realise that there are 528 10' increments in a mile, and Locate City has a radius of TEN MILES PER LEVEL.

8. ???

9. Profit!



Notes:

Snowcasting is from Frostburn. Flash Frost Spell is from the PHBII. Energy Substitution, Born of Three Thunders, and Explosive Spell are all from Complete Arcane. Locate City is from Races of Destiny.

With all metamagic feats applied to it, the Snowcasting Flash Frost Energy Substituted Born of Three Thunders Explosive Locate City is a 4th level spell.

This can be accomplished with a human wizard 7, for a 70-mile radius nuclear blast. ( You get all feats needed at level 6, but Human Wizard 7 is the earliest you can cast a 4th level spell.)

You MAY want some protection while doing this, as you are within the spell area, too. As such, if YOU fail the Fortitude and Reflex saves, YOU get ejected to the edge of the spell and take the maximum amount of damage possible (In the case of the level 7 wizard, 36960d6 damge, for an average of about 130,000 damage).