Napa County is following the Boy Scouts' motto: Be prepared.

A multifaceted -- and fictitious -- disaster scenario unfolded last Thursday as representatives from county agencies gathered in a training room at the Napa County Sheriff's office. On this day it was to be known as the Sim Center, the nerve center for a series of simulated emergencies.

A magnitude 6.5 earthquake centered near Pueblo Avenue in west Napa; an overturned school bus with injuries and possible fatalities; a riot on the grounds of Napa State Hospital; a man fatally shot by sheriff's deputies in Rutherford, all were taking place within three hours.

Shortly after noon, Neal O'Haire, the county's emergency services manager, told the group, "You were awesome. There was a lot of disbelief early on, but we kept the theme going."

Indeed, what started out as an exercise quickly gained an unusual sense of realism, and many of the participants became emotionally involved.

It was largest disaster drill ever conducted by Napa County, involving virtually all local government, emergency and law enforcement agencies, with 10 separate coordinating offices scattered throughout the county. Here's how it happened:

Shortly before 9 a.m.: The first of more than half a dozen video clips is run simultaneously for cities, emergency responders and county agencies up and down the valley. Cable channel 28 is in the midst of a newscast and the staff meteorologist, played by Barry Martin, is delivering his forecast as the temblor hits.

Chaos reigns, and the three hour disaster simulation is under way. "Be gentle with them at first," said O'Haire, admonishing his crew to go easy as they begin to place calls to emergency command centers set up throughout the county. "We'll increase the heat as we go along."

The calls start using roughly scripted information to see how their targets respond.

9:10 a.m.: Early calls to the city of Napa go unanswered. A caller gets the bureaucratic shuffle at Napa State Hospital without getting through to the information officer. There is no answer at the NSH security number.

Lots of noise in the situation room as the pace picks up.

Michelle Bonit at Queen of the Valley Hospital is one of the first to provide substantive information. "There's some damage to the old section of the hospital," she reports. "No injuries at the facility."

A spokeswoman at Yountville Town Hall said buildings have collapsed at the Veterans Home, and there is a fire at the Seventh-day Adventist Church.

9:20 a.m.: Back at the city of Napa, veteran disaster official Peter Dreier, the housing authority chief, is armed with good information. The quake on the west Napa fault has closed the First Street overpass. The Opera House is one of several downtown locations reporting fires.

9:26 a.m.: Julie from Yountville initiates a call to the media with an update on damage.

9:30 a.m.: The second TV clip plays, and we learn the Maxwell and Butler bridges are OK, but bridges around the Bay Area have closed down for inspection.

A "massive rock slide" north of Calistoga has closed roads. Large wine tanks at Beringer in St. Helena have ruptured and wine is pouring across Highway 29.

As details unfold, callers are ordering shovels, medicine, volunteer helpers and other items.

"I want to start stirring things up," says O'Haire. "It's going too smoothly."

9:40 a.m.: The phone at Calistoga's emergency operations center is busy. A second call is referred to Calistoga City Clerk Su Sneddon, who has word of the first fatalities that occurred as the Hydro Bar and Grill collapsed.

A number of agencies set up hasty news conferences. These were best for the broadcast media, who treasure the immediacy of the information. The constant updates prove valuable in order to post information to the Register's Web site.

10 a.m.: Just as the NVUSD's news conference starts with information on how parents can pick up their children, the third video clip runs.

Channel 28 reports the area around the Napa County Airport was hit hard. The main 5,800 foot runway has been reduced to a workable length of 2,500 feet and is to be used for helicopters only, no fixed-wing craft.

SFO and Oakland International are temporarily closed as well, bringing commercial air traffic in the Bay Area to a virtual halt.

A warehouse near the Napa airport collapses.

Former Napa Police Chief Dan Monez, now the executive director of Channel 28, interviews Queen of the Valley officials who set up a triage tent for screening the injured.

10:10 a.m.: American Canyon emergency officials call with updated information on power outages, injuries at Donaldson Way Elementary School and a hot line for the public.

10:20 a.m.: Gabrielle Avina, acting Napa County fire marshal, is covering as public information officer for the county, but is difficult to reach. Theresa Richmond of Health and Human Services reports that 67 bodies have been recovered from the rubble in Calistoga.

A busload of patients arrives at Queen of the Valley and all triage sites are busy.

10:25 a.m.: An attempt to go right to the top -- county CEO Nancy Watt -- failed (she was on vacation). Her assistant, Britt Ferguson, was also unavailable, so it was back to the designated information people. Avina said an information center was being set up on the ground floor of the county's administration building.

10:30 a.m.: The next video segment contains a lot of "unconfirmed" information on building collapses and dam failures and features an interview with Napa Mayor Jill Techel.

She reassures viewers that things will be all right. "We've had a few disasters before," she says. "We do have plans. Together we'll get through this."

10:35 a.m.: Word comes that patients are rioting at Napa State Hospital. Calls to NSH information officer Lupe Rincon do not produce results, and security chief Brian Banducci's listed phone is unanswered throughout the drill.

A little later, hospital administrator David Graziani fills in the blanks. "Some of our people got a little anxious," he said. "Everything's under control."

Psychiatric assistance, not just at NSH, but elsewhere, is provided by the county's Health and Human Services Department.

All schools have disaster plans, and by the time the exercise hits the half-way mark, most agencies' emergency centers are functioning well.

Like the NSH "riot," other incidents run through the rumor mill before being confirmed or quashed. Word comes that sheriff's deputies shot and killed a man at La Luna market in Rutherford. Turns out he had to be subdued with a taser gun, and peace was quickly restored.

Sheriff's deputy Tracy Stuart plays roles of distraught parent, irate citizen and TV news reporter as she calls various agencies to test their capabilities. At one point she is acting as an attorney who calls the Veterans Home in Yountville , threatening a lawsuit because the state approved a golf course on a known fault line.

11 a.m.: Another TV segment begins as the phone rings with a response from Rincon at NSH. She confirmed what Graziani reported, adding that counseling is continuing for those in need, and there were no injuries as a result of minor unrest at the facility.

The private sector also plays a role. Kate King, Napa Chamber of Commerce executive director, calls contractors and suppliers with equipment and materials to move in and help the public agencies. "We were used quite a bit in January," she notes, referring to the New Year's Eve flood.

11:28 a.m.: On Channel 28, Monez interviews a harried St. Helena school administrator who is defending the district's policy of releasing students as irate parents looked for their kids.

11:35 a.m.: Dreier says from Napa City Hall, "All hell's broke loose."

Napa asks Fairfield to send assistance as Highway 29 remains closed and levees south of town break, flooding agricultural lands. There are numerous casualties and fatalities, but no firm numbers.

11:40 a.m.: American Canyon reports gas clouds from Contra Costa refineries are moving toward the community, and ask for help in telling residents that they should "shelter in place."

Any additional security that can still be rounded up is organized for a mid-afternoon visit by the governor. A presidential visit is expected tomorrow.

11:58 a.m.: In the final TV segment, Board of Supervisors Chairman Bill Dodd praises the professionalism of county staff.

There was a brief recap of the day's events, but the real analysis will go on over the next month as evaluators gather data. Early indications are the exercise was a success. "I'm really pleased with the way it came off," said O'Haire.

He said the biggest problem was closing the loop on some of the simulated problems and the multiple calls needed to reach resolution. Some thought the exercise was too fast paced, but O'Haire said that within three hours of a major earthquake, things are going to be moving fast.

Funding for the drill comes from a grant, $60,000 this year, from the state's Office of Emergency Services.

A similar event is planned for next year.

"Napa County today is better able to deal with a disaster than it was yesterday," O'Haire said.