Monday morning the temperatures were in the single digits with thick fog. This combination resulted in a beautiful view of frost coating everything. This is called rime ice and it is when liquid droplets, from the fog, freeze on contact to trees and other objects.
Rime ice is from freezing fog and is denser and harder. Hoarfrost is frozen dew and forms with no fog and is lighter and softer.
An opaque coating of tiny, white, granular ice particles caused by the rapid freezing of supercooled water droplets on impact with an object.
A deposit of interlocking crystals formed by direct sublimation on objects, usually those of small diameter freely exposed to the air, such as tree branches, plants, wires, poles, etc. The deposition of hoar frost is similar to the process by which dew is formed, except that the temperature of the frosted object must be below freezing. It forms when air with a dew point below freezing is brought to saturation by cooling.