There is no visible built in anchorage on that blind, so it was likely anchored with augers screwed into the earth and hooked to its top corners with cable or chain. That, or it popped, as I can't see what little dirt would be atop that front section being nearly enough to hold a blind with so much displacement down.
Most South Louisiana field pits are held down with "dead men". Either the bottom of the blind extends out a foot or so beyond its sides (front and back) or, more commonly, two or three angle irons are welded across the pit's bottom so that it sticks out that foot or so (front and back) and 2x12s or other stout wood laid across those "feet" before burying. Then, when buried, there's enough dirt on those dead men to hold the blind down.
If you think I'm wrong, you might be right.