Some 26.5 million years ago a nearby volcano erupted spewing out huge masses of ash and pumice. In the end over 2000 feet (610 meters) had accumulated, hardening into rock. It is the weathered remains of that rock that gives the park its strange and beautiful appearance. Because of the cold and windy weather we didn’t hike nearly as much as we did when were last here some 16 years ago, but then again, we are also some 16 years older.