It was 2 p.m. on Friday when all of the sudden the unthinkable happened. Without warning, the Piscataqua River Bridge on I-95 collapsed, killing 12 people and injuring 60 others. Six people are listed as missing.

As Portsmouth firefighters, police officers and first responders race to the scene and the media converges, volunteers throughout Rockingham County and Strafford County get an important phone call, e-mail and text message to muster a Family Assistance Center very quickly to help those who lost loved ones.

This was the table top exercise that Paul Deignan, a disaster behavioral health coordinator with the New Hampshire Department of Health and Human Services, laid out for 34 Seacoast area emergency planning coordinators and volunteers at the Portsmouth Community Campus on Friday morning.

Deignan listed a number of different mass casualty events that could take place in the Portsmouth area and New Hampshire at any time that ranged from a plane crash at Boston-Manchester Regional Airport to the bridge collapse and even something similar to the Sandy Hook Elementary School shootings that happened in Newtown, Conn., in December.

When it comes to this events, Deignan said any number of natural disasters, man-made accidents and mass shootings will require a Family Assistance Center to be established quickly that can deal with all of the issues that will result.

“We need all of these people present during a mass casualty incident,” said Deignan of the community volunteers, the American Red Cross, doctors and nurses from area hospitals, as well as officials with state and federal agencies.

Friday morning’s event was hosted by Mary Cook, the public health and safety coordinator of the Seacoast Public Health Region in Exeter and the Safety Council of Strafford County.

The work required of Family Assistance Center volunteers can be very demanding and stressful as family members of victims show up and want answers about their loved ones, Deignan said.

Deignan, who helped staff the crisis center at the Greenland Central School following the shooting death of Greenland Police Chief Michael Maloney on April 12, 2012, said Family Assistance Center volunteers need to have three qualities:

• They cannot be a family member of victim
• They cannot have experienced a recent traumatic event
• They must be able to perform duties under stress with empathy, not sympathy

Deignan said that if the volunteers do their jobs well, the community and family members of victims will appreciate it and it will help them get through a difficult time.

Deignan said the types of people that may be needed at a Family Assistance Center include interpreters and people who know how to work with others with special needs. Clergy would also be helpful to help family members of victims, he said.

Deignan said is also important for communities to identify suitable facilities for Family Assistance Centers that would be large enough to accommodate a large group of people as well as have private spaces for one on one counseling. He said they also need to have adequate restroom and dining areas and offer extensive telephone and Internet service.

In some cases, hotels with conference center facilities located close to a mass casualty event would be a good choice, Deignan said.

When asked if the state is better prepared to staff Family Assistance Centers today than it was a few years ago, Deignan said the state is much more prepared to respond. He said the state has a Family Assistance Center plan that he shared with the 34 Seacoast area emergency coordinators and others who were in attendance for Friday’s training and the state is constantly looking for ways to improve it.

Deignan said the New Hampshire Department of Homeland Security and Emergency Management office understands the state could experience any kind of mass casualty event at any time and takes its planning very seriously.