This is the 6th book in Rachel Caine's Weather Warden series. This book finishes off the story in the second set of trilogies this series is so far comprised of and sets up nicely for the start of another trilogy.
Weather Wardens help control the weather; calming storms, fighting wildfires, and bringing rain to arid farmlands. Good books but you'll want to start with Ill Wind, the first book in the series. Joanne Baldwin is a Weather Warden who finds herself in trouble with the Council of Wardens when it appears that she killed a senior warden.