Hoar Frost Photography

by Dr. Robert Berdan
March 26, 2011

Robin feeding on Saskatoon berries covered in hoar frost - makes me wonder if the birds like Saskatoon ice-wine?

Officially it's Spring time, but looking outside today you wouldn't know it - we have several inches of fresh snow and heavy hoar frost covers almost everything. Last week we had a few warms days and a fair bit of snow melted, but then a cold front moved back down from the north as it often does in Spring. The warm moist air mixes with the cold air and forms fog. I know when it's foggy out at night and cold their is a good chance of hoar frost in the morning. Hoar frost forms when the air is supersaturated, as the air cools the water vapor freezes on anything that is colder then the surrounding air. The scientific term for hoar frost formation is deposition, a process in which a gas (water vapor) transforms into a solid (desublimation). When hoar frost forms on the ground in mountain areas it can trigger avalanches. However, for nature photographers it can be a blessing and offers opportunities for interesting landscape and close-up photographs. Most of the photos in this article were taken on March 25 during a short walk near my home in Calgary.

Hoar frost on Shrub

The name hoar is derived from old English meaning showing signs of old age in reference to the frost that forms on trees and branches that looks like white hair. Hoar frost is a beautiful form of ice that make just about anything it covers photogenic. Hoar frost can take on many shapes including: needles, cups, plates, fern-like and feather-like forms. To capture these beautiful ice forms a macro lens or telephoto lens with close-focusing capability is ideal. I also recommend using a tripod for the sharpest pictures. Most of the close-up pictures in this article were photographed using a Canon 300 mm F4 lens (between F4-F11) on a Canon 7D camera at ISO 400. Some of the pictures were taken with a wide angle lens (17-55 mm). As with most forms of winter photography I set my exposure compensation to +1 EV so the white crystals would appear white instead of gray. If you are shooting RAW files you could adjust the exposure afterwards in Adobe Photohop's Camera RAW.

Fine crystals of ice cover this small shrub near my home along the Bow river in Calgary, AB

Fence with hoar frost

Close-up view of fence showing the ice crystals

Hoar frost crystals on grass

Hoar Frost on blades of grass

Ice crystals on shrub

Hoar frost on shrubs and fence at sunrise along Old Banff coach road - temperature was -22 °C on this morning

Wid angle view of trees north of Calgary covered in hoar frost - remember to set your camera to +1 EV to properly expose
a white scene like this.

Plant frozen in ice has small ice crystal on its stem

Hoar frost crystals resembling pine needles

Ice crystals on plant stalk

Ice crystals on leaves and rose berries

Water in its many frozen forms is an amazing substance. Not only does water make life possible, it also makes life interesting and gives nature photographers a good reason to get outside and take pictures. Water is the only substance that I am aware of that when it becomes a solid (ice) it become less dense, the molecules move further apart allowing ice to float. If ice did not do this life as we know it might not be possible on earth. You might think about that the next time you take your camera out to photograph ice crystals and hoar frost.

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