Dowsing?

[Shell B]

There's some perfectly explainable abilities that can be called dowsing by some. I have done enough utilility work that I can see really subtle changes in the grade, vegetation, moisture content, where pipes or cables have been buried. These are really hard to explain, but I can look over an area and start digging very carefully and locate stuff more often than not. Some of it is knowing where it would logically run, but other times it is just a random pipe and I see little clues that I put together for a field hypothesis.
Some 'dowsers' have used these same sets of skills to back up their action, so to speak.

It's the same for every prediction in history that some scam artists has tried to pass off as woo. They use a few skills to read a person's facial expression or body language, check out the lay of the land for water, etc., and boom, it's magic!