Considerations by cold moonlight


Cow-Calf Commentary

KIMBALL, Neb. – At 3 o’clock in the morning on the third day of the new year, I bundle my freshly laundered bedsheets, trudge through the crusty, sun- and wind-burnished snow, and hang the sheets on the clothesline.
It’s nighttime, of course, but it’s far less dark than most winter nights. The sky is clear of clouds and clotted with the bright pinpricks of stars. Orion is standing tall to the south, and the Big Dipper – handle pointing northwards toward the Pole Star – stands almost overhead. The Milky Way – our home galaxy – is a star-studded pathway across the heavens. The stars are not as bright as they are on many other winter nights, for they share the sky with a barely-waning full moon.
All around me the nighttime air seems to glow with reflected moonlight. The moonlight is itself reflected sunlight, and by the time it sets the night air aglow and registers on my retinae, it’s reflected again from the broad, white snow cover that stretches from horizon to horizon, all around.
The night air is crisp and cold – about 18 degrees. This is well below the freezing point of water, so what am I doing hanging wet sheets on the clothesline? How can they possibly dry if the water they now contain is locked away as
crystalline ice?
The answer is sublimation. Water is an incredible substance, and sublimation is one of the proofs of that statement. Sublimation is the transition of solid phase water (ice) directly to gas phase (water vapor), without passing through the liquid phase. It’s the reverse of the process that puts frost on your windshield, which is known as deposition.
At temperatures below the freezing point of water, at most surface atmospheric pressures and particularly in dry air, ice will sublime when just a little bit of energy is added to the equation. During the day, this energy often comes from sunlight. As the photons rain down and collide with crystalline ice molecules, they provide just enough kick for the ice to flash to vapor and waft away. When conditions are just right this phase transition can cause a spectacular show as fog erupts from sublimating snow cover.
At night, however, there is no direct sunlight, and reflected sunlight – as beautiful as it is – doesn’t provide enough kick to drive the transition. So how will my sheets dry?
Never fear, the atmosphere itself will provide the needed energy input, so long as there’s just a touch of breeze. It’s not much of a breeze on this early January morn, flowing from the north-northeast at 16 mph, but it’s more than enough. By the time I’ve finished with the clothespins flash-frozen water ice is already leaping into the sky, molecule by molecule, as newly liberated water vapor. At this rate, the sheets will likely be entirely dry before the sun pokes its head above the horizon in a couple
of hours.
With frozen laundry sublimating on the clothesline, it’s time to stop and smell the roses, in a manner of speaking.
There are few things more awe-inspiring than exploring the world on a crisp, clear, moonlit winter’s night. On this night, the breeze is less than comfortable. It’s not bad, but it’s blowing down from Canada across thousands of miles of snow and it’s cold. I’m dressed warm and well for the conditions, in layers and with good socks and boots and gloves, but the probing, icy wind still finds chinks in my thermal armor and sends shivers down my back. After a few minutes of acclimatization, though, the spectacular beauty of this winter night pushes discomfort to the side, at least for a while.
The prairie has a mottled, monochromatic look. It’s mostly snow covered, but here and there dark outcroppings of taller grass create darkened outposts where they stand proud of the snowfield. Windbreaks make longer, darker, straighter, lines against the white background, and those windbreaks are teeming with life. Mice and voles are out and about, foraging for energy and nutrients among scattered seeds. Owls and coyotes and weasels are out too, looking for tasty rodents to provide for their own sustenance.
Cows are loosely bunched where last they were fed. Many are laying up in the hay detritus, quietly chewing cud and enduring the hours of darkness. Others are grazing the same detritus, efficiently (more or less) cleaning up the hay. A few cows stand off from the rest, grazing clumps of taller grass where it erupts from the snow. There’s a warm bovine smell surrounding the cows, further proof of the vitality of life, even in the depths of winter.
Away from the prairie, farmers’ fields make a pattern of alternating bright and dull stripes across the landscape. Fall-sown fields of winter wheat are covered with pristine snow. I can’t help but wonder how those plants fare, because they were not yet dormant when the potentially killing cold arrived on the first day of winter, and the present snow cover didn’t arrive until Christmas Eve.
Alongside the white stripes of wheat fields are darker stripes – wheat stubble and corn stubble and hay stubble, each with slightly different shades of darkness, or at least non-whiteness. Moonlight reflects from burnished snow and casts the tracks of antelope and rabbits in sharp relief.
As I meander around the winter landscape, chilled and shivering yet warmed by the amazing beauty surrounding me on all sides, I can’t help but be aware of my very great good fortune. Few people have the opportunity to see and feel and experience this thing that I so often take for granted.
I am truly blessed.

Advertisement

More In Opinion