When you and twenty-five of your friends stand on a roof above of a high traffic pedestrian walkway and choke the chicken over hundreds of people. This is an enviornmental phenomenon which occurs at any time of the year, not just winter.
Joe: dude were you walking through the quad yesturday???
Mark: No, why Joe?
Joe: Hundreds of us walking to class experienced a snow like substance falling upon our heads, but it was a little bit goopier
Mark: Shit dude, I forgot to tell you it was going to Vermont snow storm!!!!
Mark and twenty-five of his frat brahs stood over the quad at the University of Michigan and brought Vermont's weather to Ann Arbor.