Geology

Mountains dominate most of the national forests in Washington and Oregon.  Some are ancient- like the Blue Mountains of southeast Washington and northeast Oregon.  Others are much younger and continue to remind us that geology is dynamic- the impressive Big Obsidian Flow on the Deschutes National Forest is only 1,300 years old while Mount St. Helens on the Gifford Pinchot National Forest lost 1,314 feet of elevation when it erupted in 1980.

 

Volcanoes of the Cascade Mountain Range:

• USGS Cascades Volcano Observatory: Volcano information for the Cascade Range Mountains from British Columbia through California.

• USGS Volcano Monitoring: Three Sisters Area: Information for Central Oregon.

• USGS Volcano Monitoring: Mount St Helens: Information and live-data for Mount St. Helens in Washington.