Mount Saint Helens in Washington state released thick plumes of steam and gray ash Friday, following warnings from scientists that an eruption could be coming. A 1980 eruption killed 57 people. However, scientists say another devastating eruption is unlikely.

Thousands of small to moderate earthquakes during the past week alerted scientists that something is happening beneath the lava dome of the Mount Saint Helens crater. A section of glacier near the southern edge of the dome fractured and began rising Thursday.

Friday's eruption was the first in 18 years, and geophysicist Evelyn Roeloffs of the U.S. Geological Survey says it was well below the levels of the devastating event of 1980. She says ground movement should provide warning if a larger eruption occurs.

"We were not envisioning a major eruption at this point, so it's possible that this is all that's going to happen. However, we're not going to presume that, and we certainly are pretty sure that we're not going to have anything else happening without some more increased seismic activity."

Major eruptions of Mount Saint Helens in May 1980, blew off the top of the mountain, destroying 200 homes and flattening the foliage for many kilometers. Fifty-seven people, including loggers, campers, reporters and scientists, lost their lives. Volanic dust was scattered over much of the northwestern United States, disrupting commerce.

Many trails and campgrounds in the area have been closed in recent days, but onlookers have flocked to a volcano observatory just eight kilometers from the crater. Officials worry that if a larger eruption occurs, it could cloud the skies with dust and ash and possibly disrupt air traffic in the region.