The only known historical eruptions of Acatenango volcano occurred in the 20th century, between 1924 and 1927 from just north of the summit peak (Pico Mayor) and again in December 1972 from the saddle between Yepocapa and Pico Mayor. These phreatic explosions generated ballistic volcanic bombs that fell near the summit craters and fine volcanic ash that fell up to 25 km away.