I am not sure if you read the article or not, or just looked at the pictures and even then I do not see the logic of what you are saying. For one this happens around the same time of year, and in other parts of the world as well. Chemtrails are from any research I have read are sprayed over densely populated areas and they would not seem logical for such a dense cloud to be done on a remote area with 178 people. Also since this was going on long before Chemtrails were even thought of ,does not make sense unless for hundreds of years they have picked this one area and done the exact same flow pattern, and in a few other areas which have the same patterns to create such a formation.
Below are more links to more weather data for those who can see the natural wonder and mystery that earth holds. Not everything that happens has to be from the PTW or Alien which has a very wide measure of interpretation. Although yes the PTW or other entities have their hands in things, still nice to see things from an all round outlook, and the miracles of our Earth. Not every cloud is nefarious, and I have never heard of gliders pilots seeking chemtrails to ride on as I have never seen ones of this density or heard of any with this kind of motion or wind involved. Nor have I ever heard evidence that chemtrails have been happening for hundreds of years.
Here are some more sites to go to if anyone is interested in natural phenomenon. Although I am aware of the many conspiracies the biggest conspiracy is having one become gullible into believing everything is one.
http://www.morninggloryaustralia.com/
http://en.wikipedia.org/wiki/Morning_Glory_cloud
http://www.dropbears.com/brough/
I see you changed the statement "nice chem trailing" to question marks at the end now, it is always good to question ones statements and thoughts. I have often changed mine as more information is presented, or balancing of analysis with the heart.