A thin, watery layer coating the surface of ice is what makes it slick. Despite a great deal of theorizing over the centuries, though, it isn't entirely clear why that layer forms.

Winter Storm Fern, a rare convergence of Arctic cold and Southwest moisture, seems set to bring Arctic weather to many parts ...

When you step onto an icy sidewalk or push off on skis, the surface can seem to vanish beneath you. For more than a century, scientists have debated why ice stays slippery, even well below freezing.