HIghways bosses say there is a risk of 'hoar frost' across Warwickshire as temperatures plummet. They say that the minimum road temperature tonight (November 20) could be as low as -4.9C.

"Depositional frost is also known as white frost or hoar frost. It occurs when the dewpoint (now called the frost point) is below freezing.

Certainly no pen-description can do justice to the delicate beauty when the sun suddenly broke through the clouds and shone upon this forest of frost-ferns.

(WLUK) -- Hoar frost appeared in Menasha Friday morning at Jefferson Park.Tim Sweet sent us these pictures and video of the phenomenon.The National Weather Serv ...

A black frostoccurs when the cold is so intense as to freeze vegetation and turn it black, without the formation of hoar frost. Advertisement Advertise with NZME. Advertisement Advertise with NZME.

The feather-looking ice with sharp angles is a good indication that Portland’s icy spots are hoar frost and not rime ice. Two frosty formations that are easily mixed up.

"These recent frosty days sent me on a hunt to remind myself once again of the difference between hoar frost and rime ice — as they tend to look virtually the same until you get an up-close look." ...

Rime ice is commonly confused with hoar frost because of a very similar appearance. The big difference between the two is how it is formed.

Let's talk about how frost comes into existence. There are two types of frost: depositional (also known as white or hoar frost), and frozen dew.

Other types of frost that we get on cold nights include a hoar frost which forms in a similar process to that of dew - the difference being that ice crystals are deposited, as opposed to water ...

Hoar frost occurs when water vapor is deposited on solid surfaces and freezes on contact, taking on the appearance of a feather shape, and usually happens on a night with light wind.