10:27 AM PDT on Tuesday, October 5, 2004

By TERESA BELL, ABE ESTIMADA and JIM PARKER, kgw.com Staff

MOUNT ST. HELENS, Wash. – Steam and ash shot out of the crater high atop Mount St. Helens early Tuesday, but scientists said it's still not the big one, yet.

KGW

Ash and steam shoots out of Mount St. Helens early Tuesday.

The blast started at about 9 a.m. and winds carried the dark ash cloud northeast, dropping about two inches on reporters and spectators monitoring the mountain nine miles away.

Geologists said the material was spewing out of several vents, unlike the day before when there was just one large vent, and a significant amount of ash was mixed with steam as the massive plume towered above the mountain.

The National Weather Service issued an ash advisory for areas northeast of and adjacent to Mount St. Helens, as well as throughout the south Washington Cascades. The advisory was to remain in effect at least through noon Tuesday.

Before the eruption started on Tuesday morning, scientists said a bubbling lake was covering part of the huge steam vent inside the crater, indicating that magma was likely rising deep inside the rumbling volcano.

KGW

Steam and ash started shooting out of Mount St. Helens at about 9 a.m. Tuesday morning.

The mountain seemed to awaken at dawn because little happened overnight, but scientists believe that Monday's large plumes shot out of the mountaintop because "hot rock was pushed up into the glacier, melted ice, and generated the steam,” according to Lori Hendrickson, with emergency management at the Cowlitz County Sheriff's Office.

“Since yesterday's emissions, earthquake energy has slowly increased to previous high values,” she said. “Visual observations show that the area of uplift, which includes part of the glacier and a nearby segment of the south flank of the lava dome, continues to rise.”

Scientists said thermal surveys show that hot cracks in the dome are opening, causing rocks to avalanche into the lake as well as onto the south crater floor.

Field crews plan to conduct additional tests Tuesday including more thermal surveys of the dome and crater, gas-sensing tests and geologic-observation flights.

Restless Mount St. Helens twice blew steam into the atmosphere on Monday and continued to show signs that fresh magma from the depths of the earth was moving towards the surface.

AP photo

Steam and ash spew out of Mount St. Helens Monday.

The heaving mountain piped up briefly after 2 p.m., sending out a small, white steam cloud that did not appear to contain any ash. Earlier in the day, Mount St. Helens sent out a 12,000-foot high plume of steam that may be the product of magma interacting with ice or water inside the crater.

As scientists continued to monitor the mountain, they theorized on Monday that these steam bursts, at least five of which have occurred beginning Friday, are building toward a far larger explosion sometime in the next few days to several weeks.

“We’re still in the appetizer stage,” said Jake Lowenstern with the U.S Geological Survey. “We’ll maybe get the soup and salad maybe served to us, and we’ll get some magma coming up, and then we’ll be ready for the main course, if that’s in the cards.”

AP

Mount St. Helens erupts steam and ash Monday at Castle Lake Viewpoint.

Though a larger eruption is imminent, the volcano isn’t expected to see a repeat of the cataclysmic May 18, 1980 eruption that killed 57 people and coated much of the Northwest in a layer of ash. That blast lopped off the top 1,300 feet of the mountain.

Instead, scientists expect a lava dome-building eruption similar to the ones in the mid-1980s.

“The most likely scenario in our view is we’re going to have more growth of the lava dome,” Lowenstern said. “That will be primarily eruptions of lava on the crater floor, but during that process, there may be some explosions, and those explosions may be relatively large, and larger than the ones we’ve seen so far.”

Despite maintaining 24-hour surveillance of Mount St. Helens and employing some of the most advanced machines available to study volcanic activity, scientists were no closer to predicting when the next eruption would occur.

“These things can happen very quickly,” Lowenstern said. “Something that starts out relatively small can grow in magnitude. We’re putting out all the equipment so we can do the very best job of trying to figure out, is this going to be a larger eruption?”

Scientists placed a new global positioning device on the lava dome on Sunday. It replaced the old one that was destroyed on Friday. They've also installed microphones to detect explosions, and a remote-operated video camera from the Hawaiian Volcano Observatory will be placed on the crater rim. More seismometers will be put on the flanks of the volcano.

Monday morning blast

KGW

A plume of steam rises from the crater of Mount St. Helens on Monday morning.

Monday’s first steam burst, occuring at 9:42 a.m., contained little ash, said Willie Scott with the U.S. Geological Survey. Within 30 minutes or so, the cloud had dissipated and the summit was clearly visible again.

“We think that something quite hot has moved up and is in contact with the glacier or with very shallow water around the glacier,” Scott said. “What you’re seeing is steam from the water.”

Scott was giving the USGS daily briefing on Monday morning to reporters when the steam cloud began emitting from the crater.

Monday morning's steam column moved slowly toward Mount Adams. The National Weather Service issued an ash fall advisory until 3 p.m. for areas east of the mountain, most notably Skamania County. Some ash fell near Cougar, Wash. at the Ape Caves, south of Mount St. Helens.

"Wow. It was amazing," said 9-year-old Alex Turchiano, who watched from the nearby Coldwater Ridge Visitors Center. "I was hoping to see lava so I could see the trees fall down and the lava flow into the water. I wanted to see what it was going to do — whether it would stop or keep going."

During the weekend, scientists detected tremors and an increase in volcanic gases that suggest magma is moving inside the seething volcano.

Volcanologists don't expect much impact outside the remote, unpopulated area around the volcano in southwest Washington. Area school districts in Clark, Cowlitz and Skamania counties remained in session.

AP

A more distant photo of Mount St. Helens erupting Monday, from the view of Castle Lake Viewpoint.

A Federal Aviation Administration spokesman said pilots within 150 miles were alerted to Monday morning's steam eruption. If necessary, pilots could avoid the plume as they would fly around a thunderstorm, said spokesman Mike Fergus.

There was no word of any flight disruptions, said Steve Johnson, a spokesman for Portland International Airport. Alaska Airlines, which had delayed flights after an eruption on Friday, remained on schedule.

The Federal Aviation Administration had implemented a no-fly zone around the Mount St. Helens crater for five miles and up to 13,000 feet as a safety precaution during the weekend. The flight restrictions weren't expected to have much impact on commercial aircraft.

Ominous signs

KGW Sky-8

Steam bursts out of a hole in the crater on Mount St. Helens.

Scientists don’t believe there is enough magma to melt the glacier and trigger landslides from the mountain.

Researchers think new magma from at least four miles below the surface is pushing its way up the volcano. Scientists are going back through their seismic records to try to determine when the magma began its journey to the surface, Lowenstern said.

Scientists were caught a little off-guard by Monday morning’s steam blast because there was little earthquake activity just before the steam jetted out of the crater. Just before Friday’s event, seismic activity was ramping up beneath the lava dome. Friday's eruption belched steam and ash for 24 minutes and sent a plume about 16,000 feet into the air that was visible all the way to Portland.

Guy Medema, a seismic analyst at the University of Washington's Seismology Lab in Seattle, said earthquakes of magnitude 2 and 3 continued after the morning steam burst, unlike a steam eruption Friday, when the earthquakes stopped for several hours.

"It apparently didn't release enough stress to shut the earthquakes down," Medema said.

U.S. Forest Service

Mount St. Helens spews more steam and ash on Oct. 4 as government scientists remained on alert for a larger eruption. This image is taken from a VolcanoCam at the Johnston Ridge Observatory.

Throughout Monday morning, instruments were recording earthquakes of up to magnitude two every four or five minutes.

Tremors usually associated with magma moving in the volcano were detected on Saturday, prompting scientists to raise the alert to Level 3, or red, signaling an imminent eruption. The Johnston Ridge observatory about five miles from the volcano was hurriedly evacuated by the National Forest Service.

Scientists also detected elevated levels of carbon dioxide and other volcanic gases, including the rotten egg smell of hydrogen sulfide,that reflect changes in the volume of magma rising within the mountain.

Monday's steam releases followed a small steam burst at 10:40 p.m. Sunday and a tremor within the mountain that lasted about 20 minutes, said Jeff Wynn, chief USGS scientist for volcano hazards.

Wynn said the lava dome within the crater had also risen another 100 feet in the dome's southern area.

"Something is driving — like a piston — something is driving up. We believe it's magma. We believe new magma is involved. And new magma is potentially more gas rich and therefore more explosive," Wynn said.

Geologist Tom Pierson told NBC's "Today" show Monday that a buildup of earthquakes since a plume of steam was released on Friday indicate that pressure is still mounting within the volcano. Geological Survey crews also observed a shift in the crater floor and on part of the 1,000-foot lava dome that essentially serves as a plug for magma, he said.

"Cracks are opening up so we know something is pushing up close to the surface right now," Pierson said.

Thousands of spectators have been drawn to the peak since Sept. 23, when it first was rocked by thousands of tiny earthquakes, the most seismic activity at the peak since the 1980 blast.

Crowds have gathered along park roads at what was said to be a safe distance — about 8 1/2 miles from the mountain — to see what happens next. Barbecues were fired up and entrepreneurs sold hot dogs and coffee to people camped along the side of the road.

(The Associated Press and Northwest Cable News contributed to this report.)