two stage chem trail

I observed a two stage chem trail on 12-13-13, a dark trail was in place prior to the jet placement of the white trail. Is this a common practice and have others observed this practice. What would or could this process contain. [Linked Image]

[img][img]http://globalskywatch.com/chemtrails/gallery/293/full/2753.jpg[/img][/img]

Last edited by apple morgan; 12/17/13 05:43 PM.