Imagine a rock slide racing nearly 100 miles per hour down Chaos Crags lava dome volcanoes at this very spot. The jumbled rocks surrounding you are the result of a series of 3 rockfall avalanches that occurred around 1660. The first and largest avalanche covers about 2.5 square miles (6.8 square km) and created this undulating landscape.

What caused the rock avalanches? Geologists believe that the dacite rock that forms Chaos Crags lava domes broke free. Years of freeze and thaw created cracks in the fragile rocks and weakened their bond. Steep-sided slopes allowed the loose rock to break free and rush downslope. Geologists describe the rocks here floating on a cushion of air during the avalanche. The rocks gained such high speeds, that air became trapped between the ground and rocks. With friction reduced, the rocks were able to flow very far. As they came to a rest on the edges of the flow, rocks in the center continued to move at a rapid rate, creating frozen waves.