This is Samuel A. Cooley, a US photographer with the Department of the South (military zone) and his crew. They photographed Mitchelville as well as the US army encampment. All eight of his Mitchelville images and lots of information about the town are available at http://www.bcgov.net/mitchelville/photos/.
Reminds me of a bad storm over the Atlantic. Fantasy: I would be sitting in front of my picture window, in my home on the beach lol, watching it roll in. I love watching God / Mother Nature at work! I just pray everyone stays safe.