Mt. St. Hellons

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…the volcano. The eruption on May 18, 1980 blew volcanic ash consisting of heavily crushed, old rock from the mountain's core as well as solidified new lava, more than 15 miles into the air. Winds carried the ash mostly eastward across the United States and in trace amounts, around the world. The ash, which fell in extremely large amounts as far east as western Montana, harshly disrupted travel, caused widespread economic loss, and resulted in many other problems.