Mount Jefferson

Lava Flow Hazards

Mount Jefferson (pointed peak in middle) and Three Sisters (to the ...

Mount Jefferson (pointed peak in middle) and Three Sisters (to the right) in Oregon, south-facing aerial view as seen from Mount St. Helens. (Credit: Pallister, John. Public domain.)

Lava flows can occur either as an eruption from Mount Jefferson or from a vent located in the surrounding volcanic region. Jefferson typically erupts the type of magma that would forms steep- sided lava domes and stubby lava flows. If lava domes form on a steep slope, the steep fronts of the flows may collapse to form pyroclastic flows. Eruptions from monogenetic vents surrounding Mount Jefferson would likely produce basaltic lava flows that travel no farther than 20 km (12 mi) from the vents. However, such lava flows can destroy everything in their paths by burial or incineration. Generally these types of flows travel slowly enough that they are not life threatening to most humans and wildlife.