These diagrams are topographic maps of Mount St. Helens in Washington state. They were made before and after the volcano erupted in 1980. What do these two maps tell us about the eruption? A. The eruption melted a glacier and caused massive flooding. B. The eruption blew out the north wall of the volcano's cone. C. The eruption destroyed most of the surrounding forest. D. The eruption did not change the shape of the volcano.