It started at 9 a.m. Tuesday, when a West Side resident called 911 to report that a loud explosion had just shattered several windows.
Within a few minutes, the Buffalo Fire Department learned a big oil tanker had blown up in the Niagara River, just below the Peace Bridge, touching off other explosions, fires and auto crashes that left more than 100 people dead or injured.
By noon, police learned that a terrorist group was responsible for the bombing, calling it a protest over "meddling" by the U.S. government in the Middle East. And 90 minutes after that, another bomb was found on the Rainbow Bridge in Niagara Falls.
It was all make-believe, just an exercise to help police, fire officials and other government agencies prepare for the threat of terrorism.
But could it really happen here?
"We hope to God that it never will happen, but we have to be prepared," said Coast Guard Lt. Joseph Gleason, coordinator of Tuesday's exercise at the Connecticut Street Armory. "We're the second-busiest corridor between the U.S. and Canada. If terrorists wanted to affect commerce between our two countries, this could become a target."
"It isn't just Buffalo. With the developments of the last weeks, the entire country has to be on a sense of alert," added Bernard Tolbert, special agent in charge of the Buffalo FBI office. "Terrorists could use our border to come into the country, and they could use it to leave."
Similar comments came from many of the 600 law enforcement, emergency and government personnel who took part in Tuesday's Joint U.S./Canada Response Exercise, billed as the largest emergency response seminar ever held in this region.
The exercise, involving representatives of 80 agencies from Western New York and Ontario, was held against a backdrop of deep concern over recent
events in the world -- bombings in Africa and Northern Ireland that killed 278 people and retaliatory strikes against terrorists by the United States.
Tuesday's daylong program was a "tabletop exercise," meaning no actual rescue units were deployed. Aside from a simulated water rescue conducted by the Coast Guard near the Peace Bridge, everything else was done on paper, over radios and in three command posts set up in the armory.
Through a series of 911 calls and radio reports, personnel in the command posts learned of each new development in the scenario.
Starting with the bombing, it became a doomsday scenario -- one calamity after another. Officials working in the command centers had to react as they would in a real-life disaster, making phone calls and radio contacts to make sure they had the equipment, personnel and know-how to handle each situation.
Three minutes after the first call about the explosion, word came that the blast had severely injured some men who were painting the underside of the Peace Bridge. Some mangled bodies hung off the girders, and several men had been hurled into the water.
Then came a report that two rowing sculls in the Black Rock Channel had been destroyed, with several people killed.
Other simulated reports came in: Forty-two cars had been disabled and dozens hurt in a chain-reaction crash on the Niagara Thruway; phone and electrical lines under the bridge were destroyed, causing communications and power problems; the city's water treatment system stopped functioning.
"In an incident like this, you're coordinating more than police and fire departments," said Chief Petty Officer Adam Wine, a disaster expert with the Coast Guard.
A massive explosion could set off a firestorm of activity involving utility companies, health-care officials, environmental agencies, water treatment plants, sewer workers and many others, Wine said.
All were represented at Tuesday's exercise, and there were even simulated media briefings.