It ain't hoar frost . . .

[Wild Skies]

. . . but, rather it's a phenomenon called rime ice, leading to some breathtaking scenery. For the past several nights here in Northcentral Wisconsin and in many areas of the Great Lakes region we've experienced dense fog during the night and early morning hours. This has resulted in almost every branch and every little twig of every tree and virtually everything exposed to be covered in rime ice. It is exceedingly beautiful and a Winter Wonderland out here right now in the Upper Midwest.

Rime ice often happens in areas of dense fog, like we have seen the past few nights. It is when supercooled water drops (in liquid form) in the air come in contact with a surface below freezing. Those liquid water droplets then freeze on contact.

Hoar frost is similar to dew and happens on cold and clear nights. This is when water vapor (which is a gas) freezes onto a below-freezing surface. Because of this process, it actually skips the liquid phase in the deposition process.