A juvenile male was flown to the Johnson City Medical Center late yesterday afternoon after a skiing accident at Appalachian Ski Mountain.  The young man, said to be 12 to 13 years of age, was hurt after he somehow skied into a tree, facial injuries noted by ski patrol, rescue and Watauga Medics treating him. The young man was found unconscious, suffering a succession of seizures that might have come from the head injury he apparently suffered in the collision with a tree.  Medics rushed him to the helipad at Watauga Medical Center for the flight to the Tennessee hospital where he was admitted.