On the afternoon of May 18, 1980, Jim Carlson was working in the yard and getting ready to grill some burgers.

On the southern horizon, a magnificently murky cloud welled up over Lolo Peak.

"I was thinking, ‘Well, I better get these burgers on,' " said Carlson, who then ran Missoula's air pollution control program. "I remember we had a brand-new grill, very shiny and black. By the time it was done, it was ash gray.

Literally.

The ash came from Mount St. Helens in Washington, which had erupted earlier in the day.

"Then I got a call from the weather service and the guy said, ‘You're going to be busy for the next couple of days,' " Carlson said. "And, boy, was he right."

The next several days were seriously busy for anybody in officialdom, as a blizzard of ash covered the town and shut down the city.

The eruption of Mount St. Helens blew away a mile of the mountain's summit, sending a thick layer of ash east and north across Washington, northern Idaho and western Montana. As the ash fell, entire communities went indoors - and stayed there.

Carlson and his colleagues explored the full spectrum of their authority as they sought to limit potential harm from the falling ash.

"We had an emergency plan for air-quality problems and while it didn't really factor in volcanoes, it did a pretty good job of setting out what we could do," said Carlson, who is now director of environmental health for the Missoula City-County Health Department.

The core of that plan was shutting down most everything in town when the air reached a certain level of particulate matter.

"I went up on the roof of the department and got our air filter and measured it," Carlson said. "The shutdown level was 1,000 micrograms and we had 17,000."

By Monday, nearly everything in town was closed, including the bars.

"We certainly had a lot of responsibilities making sure places were closed down, particularly with the bars," said Missoula County Sheriff's Capt. Greg Hintz, who was working night shift in May of 1980. "Beyond that, police work was pretty easy. The streets were just vacant."

***

Thirty years ago, officials like Carlson and Hintz used the best available technology as they wrestled with the fallout of the St. Helens explosion. But the world was a much different place. CNN, for instance, came into existence a month after the explosion.

"It's not like we exactly had the Internet and all the media we have now," said Hintz. "We were dealing with information that didn't exactly roll in. More like a trickle."

In 1980, Carlson had to go to the Health Department roof and physically take a measurement from an air filter. Now he can automatically monitor particulate levels every hour.

"There's no doubt, if St. Helens happened today, we'd know a whole lot more about it much more quickly," Carlson said. "Probably the biggest difference would be how we network with everybody else involved in emergency management. We had a plan back then, and it worked, but it's considerably more sophisticated now."

Plans don't stop ash from falling, of course, but in terms of preparing the public for a similar incident, times have most definitely changed.

"In the end, what we can do about ash is really no different, but we know so much more about the safety aspects of such a thing, and we'd be much more ready to handle it," Carlson said. "On the other hand, one of the questions we had was whether we could shut the bus company down and we did. In the end, that saved them a lot of bus engines because that stuff just tore engines up."

***

Both information and monitoring technology changed drastically over 30 years for health and law enforcement officials. And technology also opened new windows into volcano behavior.

"We've come a long, long way in understanding what volcanoes have done and what they might do," said Rich LaHusen, a hydrologist for the U.S. Geological Survey's Cascades Volcano Observatory. "Volcanoes tend to repeat themselves, and we've learned a lot more about that behavior in the past 30 years."

Scientists who once stuck pieces of rebar into the ground to monitor deformation caused by magma buildup now use GPS technology. Interferometric Synthetic Aperture Radar allows scientists to study satellite photographs for new surface deformations.

"With that, we've been able to see an area in the Sisters area of Oregon that had been inflating for 10 years," said LaHusen. "We had detected none of the earthquake activity you'd normally expect with that kind of buildup. What you see there is that the earth is sort of like taffy. If something moves slowly, the crust just bends but doesn't break."

Scientists also know much more about the gases that emanate from volcanoes.

"Previously we looked at sulfur, but that doesn't really emerge much until late in the cycle," LaHusen said. "Now we're looking at CO2, which bubbles out much earlier and gives us some insight into how much magma might be building up."

Huge databases of information, available instantly now because of the Internet, mean scientists have much better access to historical records of volcanoes around the world.

"It turns out there is written history in Japan of a volcano that had a lateral explosion like St. Helens," said LaHusen. "That let us look at the terrain around Mount Shasta and determine that that explosion was a lateral explosion."

The upshot of those changes in technology is a "better ability to predict what might happen."

"We're also working with ash dispersion models every day, looking at different scenarios," he said. "So we have better eruption history, new information about gases, GPS and much better data in real time."

All that makes it easier for scientists like LaHusen to better detect volcanic activity and for health officials like Carlson to craft a response to that activity.

Still, much remains the same.

"As much as we know, we still can't say when they're going to blow," LaHusen said. "We've got a heck of a lot of information, but they still blow up and there's nothing we can do about it."

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