Global Volcanism Program | Image GVP-02877
An explosive eruption from Mount St. Helens on 22 July 1980, seen here from the north, produced a Plinian eruption column that rose 16 km above the volcano. At the base of the column ash can be seen rising above a pyroclastic flow traveling down the N flank towards Spirit Lake. This was the third of three explosive pulses on July 22 and lasted more than two hours.
Photo by Jim Vallance, 1980 (U.S. Geological Survey).