I am writing this blog when the first official snowfall is upon us. If you live in Edmonton, you already know what winter feels like: the crisp air, the crunch under your boots, and the giant snowbanks that seem to stick around forever. But have you ever stopped mid-snowball fight and wondered what exactly snow is and how it forms? Let’s explore the science behind the stuff that makes our winters so unique and sometimes so cold that even your eyelashes freeze.
Snow starts way up in the clouds, higher than any skyscraper in downtown Edmonton. For snow to form, two main ingredients are needed: moisture and cold temperatures at or below 0°C. When the air is cold enough, that water vapor turns straight into ice crystals. These tiny crystals stick together to form snowflakes, and when they get heavy enough, they drift down to Earth. Interestingly, it can still snow even if the ground is above freezing. If the air higher up is cold enough, the snowflakes might start melting on their way down, but that melting cools the air around them, keeping the flakes mostly frozen until they land. That’s why you sometimes see snow in early spring even when it feels too warm for it.
Many people say that it can be too cold to snow, but that’s not really true. Snow can fall at any temperature below freezing as long as there is some moisture in the air. The challenge is that very cold air doesn’t hold much moisture, so it’s less likely to snow. In Antarctica’s Dry Valleys, for example, it’s so cold and so dry that snow almost never falls. Here in Edmonton, our best snowfalls usually happen when the air is around minus nine degrees Celsius or warmer, which also happens to be perfect snowball-making weather.
Every snowflake starts as one tiny ice crystal, but as it tumbles through the clouds, it gathers more crystals and grows into those delicate six-pointed shapes we love. Most snowflakes are less than half an inch across, but sometimes, when the air is calm and the temperature hovers near freezing, snowflakes can grow to be as big as toonies. No two snowflakes are exactly the same, but they all share the same six-sided symmetry.
When you look out your window after a storm, the world seems to be covered in a soft white blanket. That’s because snow reflects almost all the colors of sunlight, and when you mix all colors of light together, you get white. However, if the snow is really deep, it can look slightly blue. This happens because the snow absorbs some of the red light and reflects mostly blue light back to your eyes. If you dig a snow tunnel or poke a hole in a snowbank, you might notice that the inside glows faintly blue. Even more surprising, snow can sometimes look pink or red. This “watermelon snow” happens when a special type of cold-loving algae grows on the snow’s surface. It looks interesting, but it’s not something you should eat.
Have you ever noticed how quiet everything feels after a big snowfall? Fresh, fluffy snow acts like a giant sound sponge, absorbing noise and making the world seem calm and still. As the snow gets older, though, it can melt a little and refreeze, turning hard and crunchy. The next time you hear that satisfying crunch under your boots, remember that it’s the sound of ice crystals breaking and rubbing together. The colder the snow is, the louder the crunch.
Even though snow feels cold, it actually keeps the ground warm. Snow is full of tiny air pockets that trap heat and slow down how fast warmth escapes from the earth. Because of this, snow works like an insulating blanket. Many animals take advantage of this, digging tunnels or dens in the snow to stay warm during frigid nights. Foxes, rabbits, and other small creatures often hide beneath the snow’s surface where the temperature is much more comfortable than in the open air.
You might have heard that ten centimeters of snow equals one centimeter of water, but that’s just an average. The real amount of water depends on how fluffy or heavy the snow is. Dry, powdery snow like we get on very cold days has much less water in it, while wet, heavy snow like we see in early spring contains a lot more. That’s why your snow fort in January might feel light and fluffy, but in March, it can feel more like cement.
Not all snow is the same, and meteorologists use different names to describe snowy weather. Flurries refer to short, light snowfalls that don’t leave much accumulation. Snowstorms are steady, heavier snowfalls that can pile up quickly. Blizzards are the most extreme, with strong winds and blowing snow that can last for hours. During a blizzard, visibility can drop to almost zero, and the wind combined with the cold can create a dangerous wind chill that makes it feel much colder than the actual temperature. A day that reads minus twenty degrees Celsius might feel closer to minus thirty-five with wind chill. When you see a winter storm warning pop up, that’s your cue to stay inside, stay warm, and enjoy some hot chocolate.
In mountainous regions, layers of snow can build up and suddenly slide downhill, creating avalanches. Scientists study these snowpacks carefully to understand when and why they collapse, since predicting avalanches can save lives. Here in Alberta, the Rocky Mountains are famous for both their beauty and their avalanche zones, which is why experts constantly monitor snow conditions there.
If you’ve ever wondered why Edmonton sometimes experiences those extra cold snaps in January, you can thank the polar vortex. The polar vortex is a swirling mass of cold Arctic air that occasionally dips southward, bringing extremely low temperatures with it. When that happens, our thermometers can plunge fast, and suddenly it feels like we’re living inside a freezer. At least we can say we’ve survived minus forty-degree weather, which not everyone in the world can claim.
From its shimmering white glow to the science behind its crunch, snow is one of nature’s most fascinating creations. The next time you step outside and catch a snowflake on your mitten, take a moment to appreciate the tiny masterpiece you’re holding. Each one is a perfect blend of art, physics, and a little winter magic.
Till our next blog, stay curious, stay warm, and don’t forget your toque, young learners!
All the information in this blog was derived from the following article. Challenge yourself and read it for a more in-depth understanding of the science of snow!
https://nsidc.org/learn/parts-cryosphere/snow/science-snow
