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'The skids are greased,' says one watching scientist

The vents are open, the dome is building and the mountain continues to percolate. And some time, someday, maybe soon, Mount St. Helens could purge a column of ash miles into the atmosphere -- an outburst that could rival even that of the infamous blast of 1980.
/ Source: Seattle Post-Intelligencer

The vents are open, the dome is building and the mountain continues to percolate.

And some time, someday, maybe soon, Mount St. Helens could purge a column of ash miles into the atmosphere -- an outburst that could rival even that of the infamous blast of 1980.

Or so says the latest round of scientific theories about the ever-changing powder keg that is St. Helens.

Minute by minute, day by day, "Volcano Watch 2004" oozes into its third week today, as the nation's most restless mountain continuesto bulge, vent and release steam from its crater.

And even while seismic activity has remained relatively low since a Tuesday morning steam and ash outburst, it appears a bulge rising from the south end of the volcano's lava dome has risen up to 100 feet more during the same period.

That's a sign to scientists that molten rock may be moving upward with little or no resistance.

"You can think of it, in a way, as: The skids are greased," Jake Lowenstern, a U.S. Geological Survey volcanologist, said yesterday.

While, in all, the mountain's roughly 1,000-foot lava dome has risen about 250 feet since St. Helens began stirring again, the volcano's status remains at Level 2 alert.

In geo-speak, that's an "advisory" meaning an eruption is likely, but not imminent. Exactly when or if bursts of steam and ash or more explosive eruptions might occur is purely speculation, scientists say.

"This is probably going to be a prolonged (period of volcanic) activity," Larry Mastin, a USGS expert on the physics of volcanic eruptions, said yesterday.

Scientists believe fresh, hot liquid rock, or magma, is nearing the surface of the mountain's crater. As it moves ever closer, magma likely is coming into contact with water, resulting in the occasional, relatively weak steam bursts late Wednesday and throughout yesterday that cast a white haze around the 8,364-foot volcano.

Once magma is released, however, the mountain's demeanor could change.

Magma possessing intense heat, pressure and volcanic gases driven upward could result in an eruption with "ash columns several miles into the atmosphere," Mastin said.

More than likely, he added, such eruptions would register up to a 3 on the Volcanic Explosivity Index used to measure the force of such blasts.

There's also a "small but real possibility" of larger eruptions, Mastin said -- blasts spewing ash plumes 10 to 15 miles into the sky and registering a 4 or 5 on the index.

By comparison, the cataclysmic eruption of May 18, 1980 -- the blast that killed 57 people, downed forests and spewed ash across the Northwest -- registered a 5 on the 8-point scale.

The index operates much like the Richter scale measuring earthquakes, in that each successive point signifies a tenfold increase in force.

Though a spectacle to behold, Tuesday's blast of steam and ash -- the largest since St. Helens reawakened about two weeks ago -- likely registered only between 0 and 1 on the index, Mastin said.

Magma releases also can manifest in much less explosive ways, scientists have said. Passive, oozing lava flows are one example.

Also yesterday, scientists reiterated that sudden mud and debris flows, or lahars, are likely to accompany the volcano's future activity. At least one small lahar gushed from St. Helens' crater early Wednesday, posing no dangers.

A 400-foot-wide retention dam about 23 miles downstream on the North Fork Toutle River likely would "throttle down" any major flow, keeping communities safe, USGS scientist Tom Pierson said yesterday. A series of sensors along the river valley that detect the sounds lahars make also would give authorities hours to issue warnings, he said.

Discerning exactly what St. Helens has in store is more nuanced than merely predicting whether or not there'll be a so-called "Big One," scientists say.

"It's really not a case of either-or," Mastin said. "Perhaps the more realistic question is, 'How big are (eruptions) going to be?' "

In trying to answer that, geologists are analyzing ash St. Helens has so far belched. Crews yesterday made flyovers of the crater, trying to detect any volcanic gas releases. And scientists are keeping a watchful eye on seismometers and seismographs, global positioning systems, infrared sensors and other high-tech gadgetry trained on the mountain.

Although all signs indicate volcanic activity will continue over a prolonged period, a hazardous eruption could occur without warning, scientists say.

And that's why roads and trails within a 5-mile radius of the mountain remain closed, providing a buffer zone and lead time should a disaster occur.

Though tourists have flocked to still-open areas at the grumbling mountain's north end, areas on its south flank, which have no good vantage points of the crater, continue a slow-paced existence.

Business owners there who depend on autumn's influx of elk and deer hunters fear that more road closures are coming -- actions that would kill local economies.

But so far, forest officials say they have no plans to further restrict access around St. Helens, including to popular hunting grounds.

"We don't foresee any additional closures," said Susan Peterson, a U.S. Forest Service spokeswoman. "But then again, you can't predict when a volcano will erupt."

P-I reporter Lewis Kamb can be reached at 206-448-8336 or