Snow
Garden Clippings for Jan 13, 2018
It was the perfect place for the used Christmas tree. On Boxing Day it was my job to drag the tree out of the family room. I promptly stuck it at the edge of the cedar deck, on the snowbank that I created after my shovelling workout.
I didn’t gain any points from anyone in the family for choosing this year’s tree. After all, I had hundreds to pick from. But I felt sorry for the runt of the litter Scots Pine that I took home. Sheepishly, I had to agree with Cheryl and the boys that it wasn’t terribly pretty. Boxing Day couldn’t come soon enough.
Redemption came after I plunked the tree outside, butt first, in the snowbank. It looked remarkable! Best of all, the birds loved it. They continuously dart back and forth from the tree to our bird feeding station.
But a week later, the tree fell over. Not because of the wind. Not because the birds pushed it over. It fell over because much of the snow around the tree’s butt disappeared. Odd, because temperatures were the coldest on record, and there was no way the snow melted.
Does snow melt or disappear even when the temperatures are frigid? Does snow evaporate?
Yes, indeed. The process of snow disappearing is called sublimation, and it happens all the time. Sublimation occurs when snow changes from a solid to a vapour without first becoming a liquid. Factors affecting snow sublimation are primarily sun and wind. The more sun, the faster the evaporation. Ditto for wind.
After considerable evaporation, the top layer of snow becomes hard and forms a crust. We have all experienced a walk in freshly fallen fluffy snow. A few days later that same soft snow forms an upper crust. Sometimes the crust is so firm that it is nearly able to support your own weight.
Is it quieter outdoors after a fresh snowfall? Yes, indeed. Snow is made up of tiny crystals and after some accumulation all those ice crystals make up many points. The more points, the more sound is absorbed. As points are reduced and turn to solid ice or water, sound absorption is also reduced.
Why is snow considered an insulator for plants? Snow’s biggest ingredient is air, just like a batt of insulation or Styrofoam. A fresh layer of snow does a wonderful job of protecting tender plants, and even provides a warm and snuggly environment for mice.
A thick layer of snow also protects plants from drying winds. It was a few years ago, while visiting Traverse City in Northern Michigan that I saw a garden with a big assortment of Rhododendrons. I asked the homeowner how they survived, because even in Sarnia Lambton we are pushing our luck with tender rhododendrons. She explained that her Rhododendrons are covered in snow during the coldest months of December to March.
How much moisture is there in snow? There is quite a difference between light and heavy snow, but experts agree that snow is made up of about 90% air and 10% ice crystal.
