A runner competing in a 253-mile ultramarathon through Arizona died after a medical emergency occurred on the high-altitude course, organizers said Tuesday. The Cocodona 250, which began Monday in Black Canyon City and was scheduled to conclude Saturday in Flagstaff, was interrupted by what race officials described as a “serious medical emergency.” The runner’s identity has not been released. In a statement posted to social media , race organizers Aravaipa Running confirmed the death. “We are deeply saddened to share that a participant experienced a serious medical emergency today during the event and has passed away,” the statement said. “The runner’s family and crew have been notified.” The organization declined to provide further specifics regarding the nature of the emergency or the individual involved.…