0:50 If you’ve been outside or just looked out your window, you may have seen a frosty or icy display of winter weather. Depending on where you live, that's hoar frost or rime ice. They look a lot alike. The major difference is how they're formed. Jessie Crow Mermel is an educator and naturalist with Severson Dells Nature Center. She said when conditions are cold, clear and calm, hoar frost "forms like dew." "And it's when the water vapor -- which is in the gas form -- turns into the solid state, which is ice crystals directly landing on objects that are below freezing," Mermel said. "The water in this process never actually goes through the liquid form."