12 January 2010 No two alike you say?

Between 1900 and 2200 yesterday we were granted ½ inch of snow. The temperature last night caused most of the snow to fall in the form of plates, dendrites, needles, and columns.


This morning’s activities included brushing snow off the decks. By 0800 I’d dragged the dog, swept the deck, retrieved the paper, and rebuilt the fire in the stove. There was the feel of cold mist hitting my face but no snow was visible.

By 0930, when I suited up for the hike with Mike, we had another ½ inch of snow on the deck. The same temperature conditions were present so it was easy to see the shape of flakes falling on the black cuffs of my jacket and on my black gloves. Loki also made a good canvas for catching snow. The prevalent flake shapes were plates and globs of needles that had become stuck together in their descent. The second snowfall was wetter and heavier to move. It required a snow shovel to scrape it off the decks.

We are currently (1417) experiencing brief snow showers of variable intensity. There is a winter weather advisory for the mountains of N. Carolina. Those mountains are three miles east and south of us. While the warnings may end at the border, for informational and warning purposes, I doubt the air masses driving this weather will halt exactly at the ridges that define state borders.

The sheer number of snowflakes that fall worldwide would make it seem impossible that no duplicates exist. However, the laws of physics prevail to make it unlikely for duplicates to occur.

In the most simple flake configurations, needles, hexagonal plates, columns, the individual flakes may certainly appear to be duplicates. Resolution of distance down to one micrometer is possible in a light microscope with good quality optics. That single micrometer is about 10000 times larger than the diameter of an atom. If snow, made of only pure water, is considered, there are about 1018 atoms in a single snow crystal and 1015 of those may be different from each other. The mathematical complexities of molecular structure quickly point out the high degree of variability that exists.

“The number of possible ways of making a complex snowflake is staggeringly large. To see just how much so, consider a simpler question -- how many ways can you arrange 15 books on your bookshelf? Well, there are 15 choices for the first book, 14 for the second, 13 for the third, etc. Multiply it out and there are over a trillion ways to arrange just 15 books. With a hundred books, the number of possible arrangements goes up to just under 10158 (that's a 1 followed by 158 zeros). That number is about 1070 times larger than the total number of atoms in the entire universe!

Now when you look at a complex snow crystal, you can often pick out a hundred separate features if you look closely. Since all those features could have grown differently, or ended up in slightly different places, the math is similar to that with the books. Thus the number of ways to make a complex snow crystal is absolutely huge.”

So physics indicates the apparent truth in the tale that no identical snowflakes are created.

But once they have formed and fallen, they undergo physical interaction with wind, with air, ground, and snowpack temperature, sunlight, and other forces that cause them to lose their initial shape and to become either more or less cohesive elements in the overall snowpack. They then become highly similar in form to all those crystals surrounding them in the snowpack. Similarity does exist, then, but only after outside forces have affected the initial morphology.

There is an easier answer. When I’m brushing or shoveling it off a deck or stairs, every shovel full and every pile brushed up looks exactly the same. It is mass that must be moved using force that I supply. Every pile seems to be a large white blob of heavy, frozen water that no longer causes wonder. I’m betting even the most highly trained physicists see it that way when their hands are on the shovel.