Mount St. Helens could erupt any minute 

08:14 PM PDT on Thursday, September 30, 2004

From KING5.com Staff and Wire Reports

AP Mount St. Helens

MOUNT ST. HELENS, Wash. - Intensifying rumblings from Mount St. Helens have geologists saying it could erupt any minute.

The May 18, 1980 eruption killed 57 people and blanketed much of the Northwest with ash. The most recent surge in activity on the mountain is now a week old.

Jeff Wynn, chief scientist at the U.S. Geological Survey's Cascade Volcano Observatory in Vancouver, said Thursday that tiny quakes occurred at the rate of 3 or 4 a minute. Larger quakes with magnitudes of 3 to 3.3 occurred every 3 or 4 minutes.

Wynn said new measurements showed the 975-foot lava dome in the volcano's crater had moved 2.5 inches to the north since Monday. Before the 1980 eruption, the north flank of the mountain swelled 5 to 7 feet per day.

Wynn estimated that there was a 70 percent chance the activity will result in an eruption, although nothing like the 1980 blast.

Scientists are warning that a small or moderate blast from the southwest Washington mountain could spew ash and rock as far as three miles from the crater at the 8,364-foot peak.

A small helicopter circled the rim Thursday to download data from instruments planted on the mountain, looking for signs that it is swelling.

Air traffic most endangered

While the eruption could toss rocks up to three miles away, the biggest danger will be to air traffic.

An eruption can throw a plume of ash anywhere from 100 to 20,000 or more feet in the air, damaging the engines of planes that fail to avoid the plume.

A KLM Boeing 747 lost all four engines in 1989 after flying through the ash plume from an erupting Redoubt Volcano. The pilots were able to restart then engines, but not before the plane had dropped for two miles.

"The ash and aviation safety issue is one that we're quite concerned about," said Volcanologist Cynthia Gardner.

An FAA spokesman said, however, that there are no special procedures in place to deal with a plume of volcanic ash other than notify pilots of where it is and how big it is.

"It's not something out of the ordinary. We do the same thing with high altitude thunderstorms," said FAA spokesman Mike Fergus.

Fergus said it's up to the individual pilot to decide how to get around the plume, either by asking to be rerouted or by seeking another place to land.

Here we go again!

On Friday, scientists were planning to use a termal imaging device to see if portions of the volcanic dome were heating up.

Few people live near the mountain, which is in a national forest about 100 miles south of Seattle. The closest structure is the Johnston Ridge Observatory, about five miles from the crater.

The heightened alert has drawn a throng of sightseers to observation areas. Dawn Smith, co-owner of Eco Park Resort west of the mountain, told The News Tribune of Tacoma, "It's just been crazy the past couple of days."

A sign in front of her business reads, "Here we go again."

The Geological Survey raised the mountain's eruption advisory from Level 2 to Level 3 out of a possible 4 on Wednesday, prompting officials to begin notifying various state and federal agencies of a possible eruption. The USGS also has asked the National Weather Service to be ready to track an ash plume with its radar.

In addition, scientists called off a plan to have two researchers study water rushing from the crater's north face for signs of magma. A plane was still able to fly over the crater Wednesday to collect gas samples. Negligible amounts of volcanic gas were found.

"An aircraft can move ... out of the way fast," Wynn said. "We don't want anyone in there on foot."

The USGS has been monitoring St. Helens closely since Sept. 23, when swarms of tiny earthquakes were first recorded. On Sunday, scientists issued a notice of volcanic unrest, closing the crater and upper flanks of the volcano to hikers and climbers.

Scientists said they believe the seismic activity is being caused by pressure from a reservoir of molten rock a little more than a mile below the crater. That magma apparently rose from a depth of about six miles in 1998, but never reached the surface, Wynn said.

The mountain's eruption on May 18, 1980, blasted away its top 1,300 feet, spawned mudflows that choked the Columbia River shipping channel, leveled hundreds of square miles of forest and paralyzed towns and cities more than 250 miles to the east with volcanic ash.