The day is September 20, 2020. An asteroid having an estimated size between 300 to 800 feet is on a collision course with Earth. The projected path will likely take the asteroid across Southern California or just off the cost in the Pacific Ocean.

No need to panic. This is just a simulated high-consequence scenario discussed in the latest NASA-FEMA tabletop exercise held at El Segudo, California last October 25, 2016. The series of tabletop discussions are devised to improve the partnership and cooperation between the National Aeronautics and Space Administration (NASA) and the United States' Federal Emergency Management Agency (FEMA). Both agencies are set to lead off the U.S. response should a large asteroid is discovered to be bound for Earth.

The previous two exercises were focused on developing ways to stop or deflect the hyphotical asteroid. However, this latest scenario is a bit different since the plans developed during the first two exercises will probably not be ready if an earthbound asteroid is discovered today due to the late discovery of the asteroid. The latest simulation provides a massive challenge to emergency managers who will be tasked with the evacuation of the Los Angeles residents. Aside from developing evacuation strategies, people at NASA and FEMA are charged with finding ways to manage hysteria, prevent panic, and deal with post-impact fallout.

"It is critical to exercise these kinds of low-probability but high-consequence disaster scenarios," FEMA Administrator Craig Fugate said in a statement released Friday. "By working through our emergency response plans now, we will be better prepared if and when we need to respond to such an event."

An asteroid the size of about 25 meters to 1 kilometer would cause severe damage to the impact area while an asteroid larger than 1 kilometer will leave in its wake damages in range of global exctinction-level. "These exercises are invaluable for those of us in the asteroid science community responsible for engaging with FEMA on this natural hazard," NASA Planetary Defense Officer Lindley Johnson said in a statement.

According to Johnson, the information which are critical for the emergency manager's decision making are taken into account and will be relevant to the information they would provide to FEMA about a predicted impact. Representatives from NASA, FEMA, NASA's Jet Propulsion Laboratory, the Department of Energy's National Laboratories, the U.S. Air Force, and the California Governor's Office of Emergency Services were also in attendance during the tabletop discussions.