Nisqually Vista Walking Tour: Well-traveled Rocks

The locations of boulders throughout the Paradise valley illustrate the massive forces of mudflows.

NPS Photo

Quick Facts

Location:

Nisqually Vista Nature Trail

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The hollow rock we visited earlier and many of the boulders that are scattered through this meadow were carried down to Paradise by a lahar about 6,000 years ago. The volcano had steamed intensely for many centuries as hot gases dissolved rocks into clay. Then the weak mass of rock and clay was jostled or shoved by a small eruption so that a huge block avalanched down across Paradise. The lahar, known as the Osceola Mudflow, flowed like wet cement and spread out into a sheet over ridges and valleys. It may have been 600 feet thick when the wet mass extended nearly 20 miles down the Paradise and Nisqually valleys. Remnants almost 15 feet thick remain in Paradise Meadow. When large boulders are carried far from their origins, they are called erratics. Erratics can be found throughout the park due to the powerful forces of glaciers, floods, and debris flows that have transported them.