With Power Tools and a Ruse, 2 Killers Escape New York Prison, page 3

a reply to: TwiztidRoman

It depends on the terrain. If there are significant rivers, streams and tributaries in the area, then it is possible that the men might have waded a few miles to throw off the dogs. Obviously, unless they hit the bank regularly, they would leave no trackable scent trail on the ground. Furthermore, if there are several such waterways branching off, that would complicate matters for dog handlers to a significant degree as well, since the more routes the escapees could have taken, the more bank to search, and the longer it takes.

The longer it takes to find the scent, the harder it will be to track when it is found, and the longer it takes to make any kind of progress. It is a tricky business. Weather is also a factor, since rain can wash away certain tracks and even certain scents into nearby waterways, which again diffuses the available scent trail for a dog to latch onto. Although bloodhounds and other tracking dogs are VERY sensitive to smell, using them to track individuals whose intent is to evade capture, over a very large area is not a simple process, and involves a certain number of known values, like a start point, or an entry point into dense woodland for example. From that, a dog may track a person by scent, but it is much harder when the individuals concerned know enough to hide their scent from the trackers.

This is not rocket science. It is MUCH harder than that!