Most of us know that water expands when it freezes and runs away upon melting, leaving a gap ready to collapse. It’s one of the great forces of erosion, blowing apart hillsides, whole mountains when given a chance. The freeze-thaw cycle is the dynamite of nature. Give me a crack and I’ll blow up the world.

We’re painfully familiar with what that does to our roads as we rattle our teeth out on frost heaves and lose wheels in potholes, both of which usually happen later in the winter when the ground is still frozen and the sun is strong.

This winter has been one great freeze-thaw cycle, with the freeze often being remarkably absent in favor of much thawing. Not this time – this time the freeze was hard and the thaw came in with the breath of a herd of mammoth stampeding the tundra, and with a deluge to match it.

Meanwhile, the ice has been thick enough to venture out on the bog near to where ice blooms rim a few last water holes like collars Elizabeth the First’s neck, caught in the unstoppable process of growing a fantastic empire out of a network of air.

What makes the blooms so fantastic? So light?  It’s the magic of the water molecule that makes it act so beautifully when it is in its solid state – below 0°C/32°F/273.16 K (Kelvin). Most substances get denser when they get colder. But water is at its densest/ heaviest when it is slightly above freezing.

Moreover, in the grand scheme of things it is very unusual for water to be liquid, the combo of pressure and temperature has to be “just right” to pull it off. One of the things so magical about our earth is that we have lots of places that allow this to exist. Even with ice ages in full swing there was a lot of ocean left. 

What we know as the freezing point is part of the “gas-liquid-solid triple point” of water. In our ordinary atmospheric pressure, at just about 32°F, to go with what’s commonly used around here, water can partially exist as a gas, liquid or solid, and a small nudge in temp or in pressure can turn the whole kit and caboodle into one of those three. The intricacies of all this are lost on me. If you care to know exactly, bring a snow cone and ask the physicist at the “Ask-a-Physicist” booth at the Cummington Fair this summer (shares one with the Philosopher). We have lots of ’em around here.

In any case, that triple point is of interest of us when we are looking at the ice flowers and the frost around the water holes in the bog when it’s exceedingly frigid outside. That ice did not come through the liquid state – instead it froze right from gas in a process called deposition (the opposite of sublimation, which is freeze-drying or what happens to laundry out on the line in the winter. See this blog post). Boom, there they were while you weren’t paying attention. (See it happening in this video)

Okay, now comes the tough part. Most of us know water is haitch-two-oh (H2O). Each water molecule consists of one oxygen and two hydrogen atoms waltzing together at all times in a threesome in which the two hydrogens do not want to hit it off with each other – they are there only for the oxygen. So they stay as far away from each other as they can, given oxygen’s obvious attractions. While water is fluid everyone is whirling around pulling together and staying away in a wild party that makes our life on earth possible because there’s space for all sorts of other crap to waltz along, like the salt in our tears and the sugar in the sap of the maple tree.

But when it gets cold they all start lining up rigidly to make sure they don’t get too close for the long haul.

That angle happens to be more or less the same angle you hold your arms when you welcome Uncle Joe back to the fold after his twenty years abroad. Except water does it in any direction. Which has the molecules at odd angles to each other and forces them to line up in layers and branch outward from a center.

Voila! An ice crystal is born. From one water molecule rigidly attaching itself to another where it must. And another. Soon they start looking like look like trees. Like sharp stalks. Like snowflakes. Like flowers on the window because there they can only grow away from each other in long lines.

And we? We get to look at them and do what we do best – which is to make sense of it all by remembering what else might look like that. Or we get to lick and crunch. Or, like my friend, free a big piece and let it float down the river to see where it will go. And the miracle never ceases.