Logjam!

摘要

George awoke to the ringing of his cellular telephone. An automated voice announced that the water level at Eagle Canyon Dam had dropped below the low alarm level. He was puzzled. The spring snowmelt runoff had begun. If anything, the water should be at flood level. George dressed and began the one-hour drive to the dam. Halfway there, his cell phone rang again. This time, the voice advised that the water level had exceeded the high flood level. George was now thoroughly alarmed.