A large fin has developed in the mile-wide Mount St. Helens crater, the result of lava upsurges, the Cascades Volcano Observatory reported.
Scientists say they expect the 300-foot-tall spire -- the size of a tilted-up football field -- to collapse into the crater's expanding dome, as others have since the volcano began erupting again 18 months ago, The Oregonian reported Wednesday.
The tip of the fin is about 7,698 feet above sea level, boosted by the volcano's rising lava dome. Scientists told the newspaper lava has been emerging from a crater vent at a rate of 3 to 6 feet a day.
The volcano -- which erupted May 18, 1980, in the most deadly and destructive volcano eruption in U.S. history -- is located about 100 miles south of Seattle, and about 53 miles northeast of Portland, Ore.
Copyright 2006 by United Press International