Stormwarden by Janny Wurts

Stormwarden is the first book in the Cycle of Fire trilogy written by Janny Wurts.  As a new plot threatens mankind’s survival, three children stand at the crux. All possess extraordinary talents, but each of them is flawed. In need of all their help is the Stormwarden, last Vaere-trained sorcerer, condemned now and trapped in a desperate quandry. Originally published January 1984. This edition published 1993.