DENVER (CBS4)- Police, fire and other emergency responders must be ready when disaster strikes. They practiced their skills at Denver International Airport on Thursday and Friday.

It’s called “Operation Vortex” and helps first responders train for the worst case scenarios.

They worked in a pile of concrete that represented an office building and parking structure hit by a tornado.

“You never know when an incident may happen. It’s extremely important to know who to contact and how to work together to get through that difficult time,” said DIA spokeswoman Laura Coale.

Fifty agencies took part in the exercise. Other sites included West Metro Fire Rescue’s training facility in Lakewood and Longmont United Hospital.

The drill continues through Friday.