09:42 PM PDT on Wednesday, May 3, 2006

By ANTONIA GIEDWOYN / KGW.com

A towering slab of hot rock is growing on top of the Mount St. Helens lava dome and emitting steam from its cauldron, according to geologists.

The slab’s height is that of a football field’s width, said KGW meteorologist Bruce Sussman, who flew over Mount St. Helens during clear weather Wednesday.

“Parts of it are growing up and to the west at six feet a day… and hot spots are 2,000 degrees Fahrenheit,” he said.

Sky-8 view

Aerial view of the growing slab.

The topmost portion of the formation is already cracking, which geologists describe as typical. As new formation grow taller and heavier, chunks of rock fall into the crater floor, helping to build it up.

The climbing season at Mount St. Helens traditionally begins on May 15.

Tom Pierson, a local U.S. Geological Survey geologist, tentatively plans to lead a guided hike arranged through the nonprofit Mount St. Helens Institute to the rim in August.

"It will be great to see the new view and to take pictures to compare," Pierson said.

The volcano's explosive eruption of May, 18, 1980 killed 57 people and removed the top 1,300 feet of the once-symmetrical peak. Most of what was blown away was a lava dome built in quieter eruptions like the current one over the previous 400 years.

Mount St. Helens began showing significant activity again in September of 2004, when volcanic blasts closed many of the mountain’s trails.