Impressions
Weak episode. Nothing supernatural here. Move along.
Critique
This episode seems very out of place.
The deaths are not from supernatural causes. It doesn't advance the longer term storyline. It doesn't illuminate the characters. Seems like a filler, unless the character of Kathleen, the sheriff's deputy, becomes a recurring character.
The only other purpose I can see for this episode is to show that the phenomena they are hunting doesn't always have a supernatural cause.
Trivia
Written by John Shiban.
Directed by Peter Ellis, who has lots of credits, including Smallville, Lois and Clark, and .... Knots Landing? Falcon Crest?
Episode seemed like a conglomeration of a lot of different older movies. There seem to be elements of Deliverance (there's even an allusion to the movie in the show), Texas Chainsaw Massacre, and House of 1000 Corpses (which is itself "inspired" by the Texas Chainsaw Massacre), and The Hills Have Eyes.