The third volume of the trilogy, titled Firecat's Dream on the author's website, is still listed as forthcoming as of March 2019.
'In the midst of the worst winter on record, Rage is beset with worry. Her mother still hasn’t fully recovered from her car accident despite Rage’s successful quest for healing magic. Her stoic uncle seems to be having second thoughts about looking after her. The school bully, Logan, is increasingly malicious. And her only friend, Billy Thunder, is just a dog again. As if that weren’t enough, there’s something wild lurking in the woods around the farm. Do Rage’s dreams hint at a sinister threat to two worlds?'
Source: Publisher's blurb.