Unforeseen Occurrences During Leave. A nurse who is away on leave or vacation shall be placed on unpaid leave when unforeseen occurrences such as national disasters and/or transportation shut downs prevent the nurse from returning to work as scheduled. In this circumstance, the nurse may choose whether or not to utilize accumulated PTO. The nurse shall notify his/her supervisor upon learning of the problem and as soon as the nurse knows the day of return to work.