Mt Island Tempest was born at Mike Pryor's farm in Waynesboro, Pennsylvania. Her sire is Island King who has sired several ponies out of Misty family mares. Mt Island Tempest is a half sister to Piper's Blu Mist by Sand Piper II and two Nightmist Legend fillies through her dam Misty 2000. Her first foal is Reagan's Tsunami Mist that was born after she got out and met up with Night Storm. She is also the dam of a 2019 black pinto colt by Nightmist Legend.