Aliy Zirkle has left White Mountain, chasing Iditarod leader Dallas Seavey west to Nome. Zirkle must overcome a 71-minute deficit, a nearly impossible task unless Seavey falters along the way.As Zirkle disappeared, Seavey’s father Mitch arrived a few yards behind defending champion John Baker.When Zirkle first arrived overnight at White Mountain, she said she would focus on outpacing the racers behind her and that Seavey was out of reach. But the musher has also said today that she’ll make a run at chasing the 25-year-old down.Read more here: http://community.adn.com/adn/node/160318