Mount St. Helens, Wash. Mount St. Helens vented a new column of steam Sunday, a lazy plume that rose out of the crater of the snow-dusted volcano.
The billow of steam rose from an area where a large upwelling or bulge of rock has been growing on the dome-shaped formation of rock in the crater. The plume rose several hundred feet above the 8,364-foot volcano, and light wind slowly blew it toward the south and southeast.
The venting reminded scientists of the volcano's activity 20 years ago, when it built the dome following its catastrophic 1980 eruption.
"It's a view very, very reminiscent of the years in the 1980s during dome-building, and a few years after when the system was hot and water was being heated and vapor was rising and steam clouds were forming," said Willie Scott, a geologist with the U.S. Geological Survey.
The plume appeared to be mostly steam, and scientists said any volcanic ash that was included was probably from past eruptions during the 1980s.
The steam emission followed an increase in earthquake activity over the previous two days, with quakes of magnitude 2.4 occurring every two minutes until Sunday, when the vibrations were more frequent but weakened to magnitude 1 or less.