Here in Maryland we're all too familiar with Black Ice. Growing up in RI I hadn't even heard of it until here, but it is NASTY STUFF!! Once I was literally almost trapped in a parking lot at work; I had to crawl along the wall of a delivery dock to get into a back door, because I couldn't walk on the lot, which was covered in it. It can unfortunately pop up anywhere and you just don't see it. NASTY!