An immobile, opaque, blazing curtain of shimmering violet fire springs into existence and persists so long as the caster focuses concentration on the spell and does not move.
The wall can be any size up to 1,200 square feet and may be shaped in any manner and to any dimensions the caster desires. For example, it may be a straight wall or curved into a protective circle.
The wall may not be evoked so that it appears where objects are.
The wall of flames is impenetrable to monsters with fewer than 4 HD.
Monsters with more than 4 HD suffer 1d6 hit points of damage when they pass through the wall. The wall deals double damage to undead creatures or creatures that use cold or are accustomed to cold.