How long was the mount st helens eruption 1980?

Mount St. Helens is an active stratovolcano located in Skamania County, Washington, in the Pacific Northwest region of the United States. It is 96 miles south of Seattle and 50 miles northeast of Portland, Oregon. The eruption was the only significant one to occur in the contiguous 48 U.S. states since the 1915 eruption of California's Lassen Peak. That eruption disrupted the lives of thousands and changed more than 200 square miles of rich forest into a grey, lifeless landscape. The eruption was triggered by a 5.1 earthquake centered beneath the mountain.