Symphony No. 50, Op. 360, Mount St. Helens is a three-movement orchestral composition by the American composer Alan Hovhaness. The symphony was commissioned by former Hovhaness publisher C.F. Peters and was completed January 24, 1982. It premiered March 2, 1984, and was performed by the San Jose Symphony under conductor George Cleve. The piece commemorates the volcano Mount St. Helens, culminating in the events of its 1980 eruption, which Hovhaness had witnessed from his Seattle home.