This is an old story from last year. I will admit that the way those 5 stores were closed seems very odd and wasteful which is not Walmart’s modus operandi. Nothing about it made any sense, yet Walmart has thousands of stores so closing a few for renovations is not in and of itself unusual. It was just the manner in which they did it. There was some speculation that the closing were in retaliation for labor disputes.
All that said, I could see FEMA or DHS partnering with Walmart as part of a national emergency system. There is no corporation with the breadth of locations, large facilities, and communication/distribution systems that Walmart has. Walmart would be the logical choice, but the question remains in exactly what manner would they be used.
I agree with Tolik on the FEMA camp thing. Not a single one has been found anywhere despite the claims of them being all over the place.