The Pentagon isn't the only federal agency basing a good portion of its strategy on doomsday-like scenarios. Officials at the Department of Homeland Security also keep a list of what-if situations that serve as a springboard for departmental planning.
While the so-called "defense planning scenarios" of the Defense Department are closely guarded, the DHS "national planning scenarios" are available publicly via a simple Google search.
The Washington Post Web site offers version number 20.1, dated April 2005, while the State of Oregon kindly makes available what appears to a minor update from the same month, numbered 20.2, plus an executive summary.
A more more current version, dated March 2006, is available from the Web site of Florida's emergency management division.
On top of the list: The explosion of a ten-kiloton improvised nuclear device near a major U.S. city, causing "hundreds of thousands" of casualties.
Also on the list are attacks with improvised explosive devices, which, according to the document, could unfold like this:
During an event at a large urban entertainment/sports venue, three suicide bombers are strategically pre-positioned inside the arena. The detonation of their devices will instill mass panic and chaotic evacuation of the arena.
Occupants evacuating the arena are most likely to move toward one of several locations. A portion of the occupants will remain in the immediate area around the venue, clogging ingress for emergency responders. Some will head toward public transportation, while others will head toward parking lots to retrieve their vehicles and depart the area.
The main thrust of the attack is at the evacuation points. In the area of the main evacuee collection area (most likely on a main street outside the venue), the UA has placed a Large Vehicle Bomb (LVB) disguised as a fire department/EMS service vehicle. It is conceivable to disguise 10,000 pounds of explosives in such a vehicle, but the actual amount could be scaled down and still achieve severe effects.
UA is shorthand for the ficticious "Universal Adversary" terrorist cell.
-- Sebastian Sprenger