premise: If you were heading south on Saturday, you may have drove right through a thick cloud of smoke as captured in this user submitted video. According to Guam Fire Department acting spokesperson Cherika Chargualaf, units responded to a trash fire behind the General Services Agency in Piti around lunchtime and had the fire under control in less than an hour. The only damage reported was to old equipment stored outside. No injuries were reported.
hypothesis: The person that sent in what it looked like over the weekend was not headed north. 
reason: If you were heading south on Saturday