Vocumos Effect

Manifestation

The Vocumos Effect takes effect when a large number of (particularly low caliber) spell casters all cast spells near one another. When a significant enough amount of low level spells are cast in an area, almost all new spells cast in the area fail as the concentration of magic in the region becomes so limited that only the most powerful of spell casters can still cast some of their spells. Exceptions include very small or simple magical spells (cantrips) and abjuration magic, which seem to go uninterrupted by the Vocumos Effect.
Warfare and magical healing are often complicated by the Vocumos Effect.

Localization

The Vocumos Effect effects a three quarters to one and a half mile radius around the center point of the spell casters. The effect lasts for exactly 24 hours before suddenly dissipating.