I don't buy into the explanation that these things were created by some kind of atmospheric energy source. Using snowflakes as an example is hardly a comparison. Snowflakes, unlike crop circles are not 100% perfect. Although most are octagonal, no two sides are absolutely identical to the other. Furthermore, crop circles offer many different types of designs, while snowflakes are pretty much octagonal. Check out this photo of a snowflake, if you look long enough you will see the inconsistencies in the pattern.
And why, if this is an atmospheric phenomenon, why does it only appear in crops? Why not in grass, sand, or snow?