Basalt shapes many of the park's cliffs, ledges, and narrow cuts. Learn where these formations appear and how they influence the valley's terrain.
Columnar basalt is beautiful in photographs and less forgiving at trail edge than many visitors assume.
How They Formed |
Ancient lava flows cooled into dense dark layers that later fractured into ledges, columns, and steep walls now visible around Sentinel Hill and nearby cuts. |
Why Visitors Notice Them |
Basalt surfaces retain moisture, hold moss differently than surrounding rock, and can create noticeable echo effects when wind moves through narrow breaks. |
Management Concerns |
Steep basalt faces erode unevenly, making route marking, visitor setbacks, and rockfall observation a regular part of park operations. |