It was the day the ground started shaking - a day few people could forget.
"The scary thing is you have no control over anything!" explained Richard Andersen.
Andersen was there - It was January 17, 1994 - the Northridge Earthquake, shaking Southern California to its core. The magnitude 6.7 quake destroyed freeways, demolished homes, and caused billions of dollars in damage.
"I thought, this is just a sign. I need to get the hell out of here. I had enough!" Andersen said.
So just six months after that massive quake, Andersen relocated to Sun City, Arizona.
He may have been slightly ahead of the curve, leaving his home and heading to Arizona, but first responders say it's a real possibility as hundreds of thousands of Californians flee their homes after a big quake.
How many people? Experts say it could be upwards of 400,000!
"If there were an exodus from California, it would involve I-40, I-10, and I-8, so we need to be prepared at all levels and all corners," explains Colin Williams with the American Red Cross.
All of those cars could lead to major gridlock on our freeways, but that's not the only problem.
Back in May, the Arizona Department of Emergency Military Affairs hosted a 3-day National Mass Care Exercise in Phoenix, involving more than 1,000 first responders and officials from dozens of federal, state, local, and tribal governments. It was the largest of its kind ever conducted in Arizona.
In the drill, they worked around some different scenarios like damaged fuel lines, water shortages, reuniting families, caring for and transporting the injured, and providing temporary housing for evacuees.
Experts predict there will be another large earthquake in Southern California at some point in the next 20-30 years, but say one could occur at any time.
But the good news is, organizers of the drill tell ABC15 that Arizona is prepared, telling us the drill was their chance to put into action what has been on paper and see if it works. They're calling the mission a success.