Humid air rising from a warm river on a cold, still morning can form hoar frost on nearby trees and grasses. From fog to flakes to frigid frosts, we have been seeing all kinds of winter weather lately. While this freezing and thawing may be frustrating for ski hills, icefishermen, and winter drivers, it does set the stage for spotting some interesting frosty phenomena with some funny names. Most people know that water condenses during cool nights to create dew , and frost is its winter companion. Shimmering ice crystals form when water vapor in the air attaches to cold solid surfaces, crusting up your lawn and drawing delicate designs on window panes. Have you ever woken up on a cold, clear morning to find the whole world covered in a beautiful white coating of hoar frost ? These especially large and beautiful crystals form when water vapor in humid air settles on objects that are well below freezing, turning directly into a solid (a process called " deposition "), or bec
