Tuesday, December 21, 2010

10 Things About Snow

1. Lots of snow is good - seriously! Good snow cover is important for the winter survival of hardy perennials because it keeps the ground temperature stable. Uncovered ground is subject to rapid fluctuations, known as the freeze-thaw cycle. Freezing and thawing of the ground shifts the soil, which can heave plant roots up out of the ground. Unseasonably mild temperatures can fool a plant into budding; when the temperature turns seasonably freezing again, the tender parts get "nipped in the bud", which can affect the development of the plant or even kill it.

2. Every snowflake is symmetrical. When you examine individual flakes, some will be unsymmetrical, but this is because they have been damaged. Scientists are not certain why the crystals form symmetrically, though there are theories about surface tension and microcosmic fluctuations in temperature. (Huh?)

3. What to do with burlap. Covers and tents for evergreens in winter are not meant to keep them warm but to protect them from sun scald and the drying effects of the wind. The trees still need plenty of air circulation, so it is recommended that you not wrap your evergreens but build a frame around them to make a little tent that does not touch the branches.

4. Big snow. Snow takes up eight times as much space as liquid water. Try it for yourself: if you put eight inches of snow in a straight-sided glass and take it inside, you should have roughly one inch of water when it melts.

5. Plant 'em if you got 'em. Snow doesn't necessarily stop you from planting bulbs, if the ground isn't frozen. If you can dig a hole in the earth, you can put a plant in it, even with the snow flying around you. The same is true with bulbs. Planting season isn't over until the ground is frozen solid. (As a procrastinator, I know this from experience!)

6. Watermelon snow. Some snow is pink and smells like watermelon, but not around here. Watermelon snow is most commonly found in the high-altitude Sierra Nevada of California, where snow is present through the long days of summer. The colour comes from a kind of algae called Chlamydomonas nivalis. It's a cold-loving alga that contains bright red carotenoid pigment. The phenomenon of watermelon snow, which turns to deep blood red when compacted, was reported as far back as the writings of Aristotle.

7. Frost flowers are beautiful, ephemeral flowers made of ice. A gorgeous phenomenon in wetlands, frost flowers are the result of ribbons or hairs of ice extruded through plant stems. It happens when the sap in the stem of certain flowers freezes; high water content causes the sap to expand and squish out through thin cracks in the stem. They're very delicate, and they'll break if touched. To catch sight of them, you must find them at dawn before the sun melts them away.

8. Frost is not bad for every harvest. Some wine growers love frost and snow. Some of the finest, most world-renown wines in Canada are harvested well after the first frost; ice wines require grapes which have spent two nights at -8 degrees Celsius. And those super strong dessert wines go for well upwards of $40 per 375-millilitre bottle. On the other hand, if you're a vintner not into ice wine, a good freeze before harvest will be disastrous.

9. Where did the snow go? Even if temperatures remain stable, snow does not. If it only snowed once but the temperature remained below freezing, the snow would disappear over time owing to a process called sublimation. Sublimation, essentially, is the phenomenon where a solid (the snow) changes to a gas (water vapour) without passing through a liquid state. For deeper explanation than that, you'll have to consult a chemist!

10. Pukak snow. You may have heard that First Nations languages include a great number of words for snow. One of those words is pukak, and it describes the layer of deep snow next to the ground. This layer, though it starts as an even mass, breaks down as heat rises from the earth inducing the snow to form into ice crystals, forming air pockets. Small rodents break through the walls of these air pockets and create a system of tunnels they use to get around.

**Note - When shovelling your walkways it is a good to pile snow onto the base of trees or your shrubs and perennials, keeping the roots covered. If a salt or ice melter has been used, push the piles away from trees and shrubs' dripline area as this could poison them when it is spring and the thaw is on.