What exactly happens right after Bob... *spoilers*

What exactly happens right after Bob puts Nadine's body in the hole he digs in the forrest? He tries to wipe the dirt off his palm, and in a split second he gets an almost diabolic expression on his face. Then there's a very weird and eerie sequence where there are shots of a cloudy sky with hats flying around, muddy water accompanied by the bizarre soundtrack. This has always been such a mysterious sequence for me, and my favorite scene in the movie. But I never understood what it was about. In commentary on the DVD they say it has something to do with the hex and Dillon says that "they shot a lot of film to get that moment", but don't really explain it further. They also say that there was a deleted, or at least planned scene where Nadine talks to Bob from the grave right after he throws her in.