New Mount St. Helens lava dome grows
Formation's hot rocks cast red glow visible at night
VANCOUVER, Washington (CNN) -- A new lava dome inside Mount St. Helens' crater has sprouted a growth that extends upward nearly 330 feet, U.S. Geological Survey officials said Saturday.
The exposed rock face, with a temperature between 752 and 952 degrees Fahrenheit, casts a red glow that can be seen from the north on clear nights, survey geologist Willie Scott said. Temperatures have spiked at nearly 1,300 degrees.
"It's hot enough to glow, but it's solid," Scott said. "It's not like Hawaii lava. It looks like solid rock ... It's formed this welt, and now it's punched through."
The elongated lava dome spreads southward from the old dome, which was created in the six years after the volcano's cataclysmic eruption of May 18, 1980. Like the old dome, it is made of a volcanic rock called dacite, officials said. The growth has taken place since October 27.
The volcano has been rumbling and spewing steam since late September. Geologists say that activity points to an explosive eruption, though none believe it would reach the intensity of the 1980 eruption that killed 57 people and knocked more than 1,000 feet off the top of the mountain. That eruption also created the current crater.
Molten rock first reached the surface October 11.
Although the USGS cautioned Saturday that the eruption could become more intense, Scott said scientists tend to discount the possibility of an explosion.
"We had some of those small explosions early on," he said, and several emissions of steam and ash Friday, which discolored the snow lying on the mountain.
But "this lava seems to be moving out fairly freely," he said. "The system isn't pressurized."
Scientists, however, are keeping a close eye on the conditions, he said.
The new lava extrusion is about 900 feet long and 250 wide, scientists said last month. It is growing, as magma reaches the surface, at a rate of about 7 to 8 cubic meters, or about a dump truck-size load, per second, a rate Scott called "pretty typical for these lava dome types of eruptions."