If this week’s earthquake had hit on any other day, there wouldn’t have been much for the Senate floor staff to do other than evacuate the Capitol and wait for further instructions.

But it hit Tuesday, the day selected for Congress’s pro forma sessions. The House held its pro forma in the morning, hours before the quake struck.

Within 30 minutes of the Capitol complex evacuation, the offices of the Secretary of the Senate and the Senate Sergeant-at-Arms were creating a makeshift chamber blocks away, putting into action a plan created after 9/11, Secretary of the Senate Nancy Erickson said.

“The Senate has plans in place to ensure the continuity of the legislative process,” she said.

It’s the details that matter when it comes to preparing for an emergency, from the major (selecting secure locations) to the miniscule (making sure that the Senate seal is readily available). Other necessities in the Senate floor flyaway kits: flags, a gavel and procedural manuals.

Staffers are trained to tailor their own flyaway kits with the essentials and update them regularly, Erickson said. Had Congress been in session when the earthquake struck, more legislative clerks would have been working and equipment for roll call votes would have been available. The session also would have taken place in a space that would have accommodated more people.

Congressional offices and the Capitol Police regularly do exercises to test and tweak the plans, most recently in June.

The preparation proved handy on Tuesday afternoon.

“I was very pleased with how smoothly everything went,” Erickson said. “We try to be very thorough.”

Ian Koski, communications director for Sen. Chris Coons (D-Del.), was in Washington, D.C., with his boss for the pro forma session, which was held in Postal Square. He watched as the staff made a regular basement room into a space fit for the first non-ceremonial session outside of the Capitol in nearly 200 years. Tables were moved around to make the room resemble the chamber’s setup while video cameras were positioned to film the 22-second-long session.

“It was not particularly elegant or extravagant,” Koski said. “The Senator convened it and then recessed it, and everyone collectively exhaled when it was over. This is really a phenomenal job under shocking circumstances.”