Frosted Windowpanes

I like winter; I like snow.  I like frost and ice, too.  All of it is delightful, as long as one doesn't have to drive in it, or shovel massive quantities of it.  So when I woke to a gorgeous Christmas morning this week, after the previous day's hazardous driving, I was enchanted.  The ground was white with a whopping 1.5-2" of snow, the sky was a cloudless blue and the sun shone brilliantly, transforming the outdoors into a magical wonderland.

"Mountain Range" formed on Hall Creek - probably a good 2-3 feet long.

"Mountain Range" formed on Hall Creek - probably a good 2-3 feet long.

Back at work two days later, after the deep freeze of Boxing Day, I was in awe of the frost patterns I found out on Hall Creek when I walked out there with the four- to six-year-olds of our Winter Day Camp.  There was an incredible "mountain range" formed by the moving water, and on either side of it were fronds of feathery frost and spokes of toothpick-like frost.

Frost feathers (hoar frost) on Hall Creek.

Frost feathers (hoar frost) on Hall Creek.

In our "conference room," where staff often eat lunch, we have some beautiful frost growing on the windows that face the butterfly gardens.  When the sun hits the ice just right, it sparkles with a kaleidoscope of colors, which are nearly impossible to capture with the camera.  They appropriately call it "fern frost," these graceful lacey creations that adorn our windows.

Close-up of the frost on the conference room windows.

Close-up of the frost on the conference room windows.

It all seems so magical - and yet, the mechanics of frost formation are pretty basic:  water freezes.  Yes, it really is that simple.  

First, let's quickly review the three states of matter:  solid, liquid and gas.  Everything around you is either a solid, a liquid or a gas.  When it comes to water, you have ice (solid), water (liquid), and water vapor (gas).  We are a water planet, and there is almost always water around in one form or another...maybe not in great quantities, but it is usually there.

So, when the temperature drops below freezing, water vapor, which is in the air all around us, condenses on cold surfaces and turns directly into ice, skipping the liquid stage (at temps above freezing, it condenses as a liquid, forming dew).  Water vapor is made up of tiny tiny particles of water, and each particle finds something to cling to and freeze - this is the nucleus of the frost formation.  Additional water vapor clings to the sharp edges of this formation, and it, too, freezes, forming a tiny little ice crystal.  As more water vapor collects and freezes, the ice (or frost) crystal grows.  

Tiny imperfections on the surface where the ice is growing (like scratches on your window, or even the film/streaks left behind by window cleaners) can influence how the crystal grows.  So can wind.

The beautiful frost patterns we found on the stream are a type of frost called hoar frost (from the Old English word hoar, which refers to something being grey or white).  Hoar frost is formed when there is a lot of moisture in the air, which one would definitely have at a stream or pond...or if fog had formed overnight and then froze on surfaces.  When there is a lot of moisture present, one is almost guaranteed incredible shapes and patterns in the frost...and it will likely be a beautiful opaque white color (hence the name).  Add some wind to the picture, and you can get amazing fingers and spires of frost...all pointing in the same direction.

Most newer houses, or older houses with new windows, do not get frosty windows - a good thing when it comes to your heating bills, but kind of sad if you enjoy the beauty of frost formations.  This is because you have to have windows that are only single-paned:  one side of the glass is in touch with the cold air outside, and the other side is in touch with the warmer, moister air in your house.  When the two collide on your window pane - voila! - frost forms.  Newer windows are too well insulated - the air trapped between the two panes prevents the intimate contact needed between the cold air outside and the warm, moist air indoors.

Whenever I see frost creations, I grab my camera and try to capture them "on film."  As soon as the surface they are growing on warms up, they disappear, so I immortalize them as best I can.  But even without a camera in hand, they are a delight to behold.  So don't let the chill of this cold snap keep you from discovering the wonders of winter - get out there and explore!