The #sneckdown is now a phenomenon, with nature’s traffic-calming gaining international media coverage and photos popping up from across the U.S. and Canada.

“The snow is almost like nature’s tracing paper,” Streetfilms’ Clarence Eckerson told the BBC. “It’s free. You don’t have to do a crazy expensive traffic calming study. It provides a visual cue into how people behave.”

The sneckdown dates back to at least 2001, when Transportation Alternatives wrote: “[T]he next time someone tells you that you can’t have a neckdown on that corner or this corner because there’s not enough room, show them what happens every year when it snows.”

Clarence first documented “naturally occurring neckdowns” for Streetfilms in 2006. Seven years later, Streetsblog founding editor Aaron Naparstek coined the hashtag, and the rest is history.

Here are pics from yesterday’s storm. Keep ’em coming.