Lava Flows

Numerous hazards can occur at composite volcanoes like Mount Jefferson including lava flows and domes, pyroclastic flows, ballistics, tephra fall, lahars and debris avalanches.

Mount Jefferson is a prominent feature of the landscape seen from highways east and west of the Cascades. The volcano has erupted repeatedly for hundreds of thousands of years beginning about 300,000 years ago.

Lava flows can occur either as an eruption from Mount Jefferson or from a vent located in the surrounding volcanic region