The entire north face of the volcano was blown away and a dome has built up in the caldera since the 1980 eruption.
You can tell that the pyroclastic flow came up the hill for the right parallel with the dead trees on the ridge.
All the trees on this small mountain were destroyed because the face faces the blast.
In 1980, a major volcanic eruption occurred at Mount St. Helens, a volcano located in Washington, in the United States. The eruption (which was a VEI 5 event) was the only significant one to occur in the contiguous 48 U.S. states since the 1915 eruption of Lassen Peak in California. The eruption was preceded by a two-month series of earthquakes and steam-venting episodes, caused by an injection of magma at shallow depth below the volcano that created a huge bulge and a fracture system on the mountain's north slope.