The pool closes due to thunder, lightning, approaching storms and/or hard rain that causes the Lifeguards difficulty seeing the bottom of the pool. When lightning is detected at 10 to 20 miles away, we close the pool to allow patrons to prepare to find shelter. Lightning is one of the leading weather-related causes of death and injury in the United States. You can be struck by lightning even when the center of a thunderstorm is 10 miles away and there are blue skies overhead.