Death of Obsidian Butterflies

DEATH OF OBSIDIAN BUTTERFLIES
COST: 15 motes
Area: 30 yards wide, 100 yards long, 10 yards high
Death of Obsidian Butterflies calls forth a cascade of sculpted obsidian butterflies with razor-sharp wings. Their wingspans vary from an inch across to almost a foot. Flashing over the character's shoulders and past her sides in a glassy black torrent, they slash through the air in a patter 30 yards wide, 100 yards long, and 10 yards high. Brush, grass and small trees are cut off near the ground. Larger trees and wooden structures suffer serious damage. Stone is defaced but structurally unharmed.
When the character releases the magic, her player rolls (Perception + Occult), adding a number of automatic successes equal to the sorcerer's permanent Essence. Everyone in the attack patter not behind an inch or more of stone or several inches of wood is subject to attack.
Characters defend against Death of Obsidian Butterflies as if it were a hand to hand attack. each attack is independent, so magic and penalties that reduce the attack do not help others defend. Treat the butterflies as rolling a number of attack successes equal to those the sorcerer's player rolled, minus one for each two dice of dice penalties that circumstances impose. The attack inflicts 8L plus any extra successes in raw (pre-soak) damage. The thousands of shattered glass butterflies don't go away after the spell. Walking barefoot in the area thereafter is not recommended.