What a bad winter for ice! The cold weather began rather early; but after an initial snowy period the snow disappeared until recently. Unfortunately along with the dramatic rises and drops in the temperature we got quite a bit of rain. And when the resulting standing water froze it produced awful expanses of dangerous ice. One very frigid morning I was walking with great difficulty. Yes, I had my ice cleats on but they really were not getting a purchase; the ice seemed “harder”. And this got me thinking about ice. We all know that water freezes at 0 degrees Celsius; but then many of us assume it remains the same no matter what the temperature falls to. Doing a little research on the density of ice I read that ice does indeed become denser as the temperature drops further below zero. From the mists of memory came recollections of another temperature scale, Kelvin, and “absolute zero” where molecules cease to move. At least I now know why my cleats weren’t helping me as much as usual!
While doing this small amount of research on ice I came across another interesting bit: there still is no scientific consensus on why ice is slippery. Isn’t it wonderful how something so normal can still be mysterious. And for all of us who have taken dramatic tumbles on the ice this winter we can take some comfort.
I’ve been reading a very interesting book on the natural world in winter. In it the author pointed out that ice is lighter than water! If I ever learned that I’ve long since forgotten. He observed that ice weighs less than water and thus ice forms on the surface (not starting at the bottom) of ponds, lakes and streams. Of course! That’s why the ice cube floats in your glass of water.
In the same book I have learned a new technical term: the subnivian zone. At first I was stumped but then a tad of high school Latin surfaced to help me out: the area below the snow. This is the region directly at ground level and with enough snow it remains just above freezing. Many mice and other small rodents roam this area during winter. Anyone with a dog will know how much time they spend with their snouts pushed into the snow. Their sense of smell is drawing them to the subnivian zone because of these small rodents. When the snow melts in the spring many of us notice a network of small pathways.
Back to the subject of ice for a moment. The new Millbrook dam creates “ice sculptures” too! Until the really frigid weather, I was ready to report that the new dam no longer gave us the kinds of ice accumulations that the old dam did. That was premature. I can now report that ice does indeed form; although it is not nearly as dramatic now that the spillway is sloped.
With intense cold we often have wonderfully clear skies. And we were lucky that this was the case on the night of the last full moon. The media put us on watch for a “super moon”. I was lucky enough to see it near the horizon on January 20th at 5:30 pm. A strikingly large, beautiful golden globe hung suspended just above the horizon. And then to my pleasure the next morning I saw it on the opposite horizon.
Fans of the night sky were preparing to watch a full lunar eclipse that night. The total eclipse was predicted to occur well after midnight–much too late for me! But I did stay up to see the beginning just after 10:30 pm.
Yes, it’s cold. And yes, it’s icy. Getting out can be less of a pleasure, and often a risk. But there are still wonders of nature to think about and to see through the windows of our homes. Enjoy!
Get Out! by Glen Spurrell
