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The building material for these crystals had come from my tent mates and me. It was quite unintentional, yet all night long we had been busy producing the one necessary raw material for frost-covered tent walls: water vapor. It came from the normal business of breathing; exhalations of warm moist air rising up from our bags and then condensing on the cool nylon of the tent.

This type of crystal is Graupel — so much water forms on the original crystal that you no longer see it — only the crystals on top of crystals. (See a larger version of this image.)

If you've done a little winter camping, you know that frost is something of a nuisance. If your tent mate rolls over, a sprinkling of crystals will fall onto your face and, as you get moving, the sprinkling turns into a veritable avalanche of frost, eventually wetting jackets and bags. There's not much that can be done to prevent it. It doesn't matter whether you have a new latest-and-greatest Gortex tent or an old-style (but perfectly adequate) breathable nylon-rain fly combination. In cold temperatures, warm moist air will freeze when it touches cold nylon material. If you sleep in a tent in mid-winter, you'll have to deal with the unpleasantries of frost.

But the inconvenience of dealing with frost wasn't on my mind that morning. It was the minute, individual crystals clinging to the nylon thread and swaying above my head that caught my attention -- and wonder. And therein begins our investigation of the ultimate reality of snow.

What is so amazing about frost crystals is that the process involved in creating them is the same process that occurs on a much larger scale in the creation of snow. Snow, of course, falls from clouds where its life begins as tiny ice crystals. The crystals grow, drawing molecules from water vapor present in the cloud.

Depending on temperature and the amount of water vapor, the crystals can develop into different forms, but invariably settle on a six-sided symmetry, a structure determined by the properties of water molecules and the way hydrogen and oxygen atoms align themselves. With sufficient water vapor present, the ice crystals expand until reaching a certain critical size, when they fall toward the ground.

"The same law that shapes the earth-star, shapes the snow-star," wrote Thoreau about stellars. "As surely as the petals of a flower are fixed, each of these countless snow-stars comes whirling to earth…these glorious spangles, the sweeping of heaven's floor." We've all seen these sweepings of heaven's floor. Most can be seen by the naked eye and, like Thoreau declared, they are glorious.

After I had crawled out of our tent that cold, bright morning in the Gospel Hump Wilderness and just as the sun was creeping gratefully into our camp, a glint from my pole strap caught my eye. It was a stellar, a brilliant six-pointed star reflecting the morning light like a finely polished mirror. I stood in my tracks mesmerized by it. It was a thing of great beauty, more delicate and more dazzling than any jewel I've ever seen.

It had fallen from an ice cloud, one of the trailing clouds of the multi-day storm that had engulfed the Gospel Hump for the past week. As the storm wound down and the winds died, this crystal had formed: water molecule piled upon molecule until a perfect star had been created. Along with other stellars, it had floated gently down and landed upon my ski pole strap. There was absolutely no wind, not even a whisper of a breeze, to disturb it and there it sat before me in all its grand glory.

These, the finest among Thoreau's sweepings of heaven, are the kinds of snow crystals that stir the soul. If enough fall from the tail-end of a storm when the wind's fury has moved on with the main front, they pile up like crisp, freshly fallen leaves. They create fluff that is so light and so full of air that some call it champagne powder.

When you ski on a day like this, a day of light stellar stars, you never forget it. And when it's over, you tuck it away like the memory of a past lover, warm and inviting, burning softly, ready to be rekindled some time again, which you hope comes soon! Sometimes, if you're lucky, it comes soon, but sometimes it may be weeks, or months or maybe years. But once you've experienced it, you're always seeking it out.

I guess deep down I'm a deist: one that sees God in nature. To me, there's nothing more revealing of divine presence than to look at the world around us: the complex interplay of things, inanimate and animate, big and small, the fascinating science behind them and, of course, the natural world's incredible diversity.

Take snow; simple enough at first look but on second look, amazing beyond description and outrageously diverse. Although stellars are common, other types and shapes are swept down from ice clouds, including those shaped like microscopic six-sided fluorescent bulbs called columns, or stubby columns with a pointed nose called bullets, or tiny flat hexagons called plates.

The mechanics behind this are fascinating. A falling crystal can pass through a supercooled water cloud. These clouds consist of small droplets of water, but the air surrounding the droplets is below freezing. Normally, you would expect the water droplets to freeze and become an ice cloud, but the water droplets have just enough kinetic energy to stay in a liquid state. That makes them highly unstable. It's like a cross country skier stuck at work during a snow storm. You get unstable, antsy, ready to run out the door at the earliest opportunity.

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