Mount St. Helens has a growing lava dome, indicating that magma is moving through the volcano's crater, the U.S. Geological Survey said today.
"The volcano remains restless," Tina Neal, a geologist for the USGS, told reporters during a conference call. "The area of lava has grown somewhat."
There was no change in the alert level at the volcano, which erupted May 18, 1980, killing 57 people and pouring ash into the atmosphere. The mountain began shaking Sept. 23, and there have been plumes of steam sent into the skies.
Officials have been warning that additional eruptions were possible without warning, but they do not expect the level of violence seen in 1980. Hundreds of square miles of forest were destroyed then. The height of the mountain decreased from 9,677 feet to 8,364 feet.
The area around the mountain remains cleared, and a tourist center five miles away is closed.
The previous dome-building period lasted for about six years after the 1980 eruption and created a mound nearly 1,000 feet tall. The new dome was spotted earlier this week and could grow larger than the old one. Temperatures approached and sometimes surpassed 1,000 degrees Fahrenheit as the hot rock flowed.
"This type of lava dome is a complex and dynamic process," Neal said. "We know conditions change rapidly," and fluctuations could take place "in the days, weeks and possibly months" ahead.