Mount Shasta

With an elevation of 14,179-feet, this snow-capped mountain is the fifth-highest peak in California. It consists of four overlapping volcanic cones and has a long history of destructive eruptions of ash and lava. While it has remained relatively dormant for the last few decades, scientists believe that it could erupt at any moment. But regardless of the threat, thousands of people still come here every year for hiking, backcountry skiing, and camping. The most popular route is the Avalanche Gulch, which ascends 7,300-feet in just under 6-miles.