Everyone has seen these dust devils wondering across the desert.  Wednesday I was riding my bike from Riverside to Norco and back, and where I turned around I stopped and used a porta potty where the folks unload their horses.  When I was inside the porta potty it began rocking and shaking.  I pushed the door open and found I was engulfed in one of these dust devils.  It shook the porta potty like crazy.  Lucky I wasn't picked up and thrown!!!