The Phenomenon Of Snow: The Science, Beauty And Magic Of Snowflakes
Those first flakes floating past the window are a pivotal moment in the year, sparking exclamations of wonder and excitement at the change of the season. Snow has so much potential: rosy-cheeked fun activities and the muffled, sparkling beauty of a blank canvas that can transform into a wildlife fairy tale or paint palette with paw-printed tracks and yawning streaks of a colourful sunset.
Besides being thrilling and beautiful, snow is fascinating: from the way each individual crystal is designed to the widespread impact of millions accumulating on the ecosystems we love to explore.
Here’s the science behind the magical world of snow!
Nature’s Frozen Architecture
The story of a snowflake begins in the atmosphere as a tiny droplet of moisture forming around a speck of dust or pollen. As the temperature dips below freezing, water molecules arrange themselves into a symmetrical hexagonal shape. Thus, the only common denominator between the millions of unique snowflakes that fall here each winter is the six-sided base shape.
The temperature, humidity and atmospheric conditions the frozen speck encounters as it falls dictates the direction and shape the six arms of the crystal form and grow. Because each flake’s path to the earth through these factors is slightly different, no two snowflakes are alike.
The best way to observe flake shapes is on a dark, cold surface. Use a magnifying glass for a closer peak at the intricate structure!
If you do, you’ll notice the crystals themselves are translucent. So why does snow appear white?
Sunlight is white light, made up of all the wavelengths we perceive as distinct colours depending on which are reflected or absorbed by the object and our eyes. For example, an aspen leaf absorbs all wavelengths except green, which is reflected into our eyes. The many faces of the billions of snowflakes accumulated together on the ground or a branch simultaneously reflect, bounce and absorb all wavelengths. Thus, all wavelengths are being reflected into our eyes at once as well and unite into what our eyes perceive as that iconic blanket of white.
Snow’s reflective power also sends much of the sun’s light back into the atmosphere instead of absorbing into and warming the Earth.
Canadians know snow is more complicated than a soft white carpet—its texture and noises tell a story. Sometimes it is pillowy and light, sometimes it crunches underfoot. Snow’s physical properties are determined by temperature, which is why you know its blistering cold when you hear that distinctive hollow squeak.
Snow’s Role in the Ecosystem and Environment
Snow is a climate regulator, insulator and irrigator. In boreal forests snow can cover the ground for half of the year and account for half of the annual precipitation, and in the alpine, snow is a key variable in determining vegetation patterns.
Layers of the powdery white stuff form reflective barriers, glaciers, crucial alpine moisture retention and soil fertility. In fact, in the alpine where the surface lies beneath metres of snow, the soil might not even freeze. Anything under a foot of snow is protected from temperature changes above, trapping heat and moisture, and delaying thaw once the soil surface does freeze.
To a wild animal, snow is camouflage, an insulated highway, or a reason to hibernate or migrate. Snowfall and melt triggers migration events, with the return and breeding of certain animals and birds such as migratory shorebirds and passerines timed with the retreat of the white quilt. Snow also affects fur density and feather colour, feeding habits, travel methods, reproduction and survival. For example, deep snow makes things hard for deer and moose. It impedes foraging and movement, requires more energy to move through and makes them easier pickings for a hungry wolf. Meanwhile, bears prefer to den under deep snow, and lemmings appreciate the warmth and cover.
Snow and Human Society
Given it coats our northern world for a significant part of the year, snow is an integral element of our lives, history, culture, economy and traditions.
Snow has shaped and supported past and present ways of life and livelihoods.
Snow presents beauty and opportunity like recreation and tourism. Winter sports and activities hinge on the presence of snow to glide on, trek through and shape into portly gentlemen or ammunition.
Besides the fun, snow also creates challenges in transportation and infrastructure: some of us shudder at the thought of waking up to a fresh dump, while others relish the resulting snow days.
And in case the myriad references to powdery flakes floating in this year’s holiday songs didn’t make it obvious, snow is a key unavoidable element of our lives, and a fascinating one at that!
