Dog Hair Thicket Traditional Cache

What is the "Mogollon Shift?"


Mogollon Shift: A phenomenon noticed in the rim country, whereby coordinates mysteriously move up to 45 feet away from the cache site. This occurs even if the GPS has direct access to the sky. No matter how many readings are taken when hiding a cache, the coordinates seem to migrate an average of 45 feet away from where the cache was placed. This phenomenon was explained to me by other cachers and named “The Mogollon Shift.”
Why does this happen? Unknown, it is suspected that topography causes variation in satellite signals depending on the time of day that is not found in lower elevations.
What does it mean for cache placement? Caches placed in the rim country cannot rely on coordinates alone. It is helpful to leave a description or hint such that the cache can be found even if the GPS says it is somewhere else.
What does it mean for geocachers? If the cache is not readily found at GZ, it can be very helpful to walk in a circle 45 feet away from the cache. This tip, which came from OP Jim, has helped me find several caches on the rim.