From Claude : Jade Helm 15 was a large U.S. military training exercise that ran from July 15 to September 15, 2015. It became famous mostly because of the rumors around it.
What it actually was: U.S. Army Special Operations Command (Green Berets, Navy SEALs, and other special forces) practiced moving and operating over long distances in unfamiliar terrain. It took place on military bases and some private land, with permission, in Texas, Utah, Arizona, New Mexico, Nevada, California and Mississippi. The aim was to rehearse missions they might carry out overseas.
Why people panicked: One planning slide labeled Texas, Utah and part of California as "hostile" territory. That was just the made-up role-play scenario, but it set off rumors online:
The government was secretly preparing martial law.
The military was going to take over Texas.
Closed Walmart stores would be used as bases or detention centers.
Underground tunnels and "FEMA camps" were being readied for citizens.
The rumors spread far enough that Texas Governor Greg Abbott ordered the Texas State Guard to monitor the exercise, a move that was widely criticized at the time.
What happened: Nothing. The exercise ended on schedule, there was no martial law, and everyone went home.
It's often pointed to as a classic example of what you were describing earlier: a military drill with limited public explanation, and fear of the unknown filling in the gaps.
I could not remember all the details except I kept hearing plenty of Okies and street dwellers saying they were busy building WalMarts to house all the citizens in. My husband said they will have to build around Leslie because she is always there...boy I miss his wit/witless comebacks