Today’s post comes from Brianne Brothers, an Area Ecologist for our Southwest Parks.
Ah, snow. A substance that truly embodies what it means to be Canadian.
While many of us struggle with the idea of enjoying something that involves hard physical work and white-knuckle driving, it really is clean, fresh and beautiful.
On that note, grab a cup of coffee and get cozy by the window, and let’s explore the science of snow.
Snow formation depends on two factors: temperature and humidity.
Simply put, when the atmospheric temperature is at or below 0 degrees Celsius, moisture adheres to dust or pollen particles and eventually turns into a snowflake.
Temperature is the key here, because without cold air, this process would produce raindrops instead of snowflakes. Just like rain, when these snowflakes get too heavy, they fall to the ground and provide us with a winter wonderland (and shoveling, sorry).
types of snow
Let’s go back to our two important ingredients: temperature and humidity.
Warm temperatures indicate higher levels of humidity, which creates wet snow. Under these conditions, the edges of each snowflake melt, causing them to stick together, creating large, heavy flakes (heavy is relative when referring to a snowflake!).
Wet snow is perfect for rolling snowmen and catching flakes with your tongue. It’s also the kind of snow that makes you cry a little when a snowplow rumbles along at the end of the driveway after shoveling (always!).
Cold, low humidity conditions create dry snow. These snowflakes do not stick together and are therefore much smaller, lighter and fluffier. These flakes are often called “powder” and are a favorite at ski resorts.
It is a common misconception that cold climates also receive large amounts of snow. In fact, many of these places have little or no humidity (thinking of our two ingredients!) and therefore have desert-like conditions, like the dry valleys of Antarctica, which have almost no snow or ice cover. (Note: do No wear sandals for this desert.)
How do plants survive in winter?
Plants are master adapters. During winter there is a lack of water and, because of this, deciduous trees, such as maples, lose their leaves and become dormant (this is called “senescence” to save precious energy.
Coniferous trees, such as white pine, retain their foliage but rely on a waxy coating to prevent water loss. The conifer shape is also a good adaptation; The conical silhouette of these species allows snow to slide easily, preventing damage from snow load.
How does snow science relate to wildlife?
Snowflakes undergo several changes throughout their journey to earth. These multiple personalities are the result of changes in air humidity, temperature and other environmental factors.
Once snow reaches the ground, it continues to change over time and this process is known as age hardening. As snow ages and goes through periods of warming and cooling, it changes composition and creates different layers.
The layers closest to the ground are much warmer than the layers above, and this warming creates weak, sugar-like snow that is much less dense than other areas of the snowpack. This weak layer is known as hoar depth, and allows animals to move freely and create networks of tunnels beneath the snow cover. This world under the snow is called sublevel zone.
Next time you’re standing in deep snow, remember that species like mice, voles, and shrews are right below you having a party in this sub-nivean environment.
Glossary of snow words
Pro Tip: Use these words as often as possible to improve snow geek credit
- Frost: Basically, this is a hard freeze. It occurs when vapor in the air comes into contact with a subzero surface (such as a metal fence) and passes directly into the solid state of ice crystals. High humidity and wind can create some super cold winter formations, like the following:
- snow rain: Snow that falls with different intensities over a short period of time
- Snowflakes: Light snow for a short period of time. Little accumulation expected with gusts
- Snow Showers: Brief but intense snow showers that can cause substantial accumulation (shout out to Ontarians who live near the Great Lakes – you know what this is!)
- Sleet: Raindrops that freeze before hitting the ground. These tend to bounce and hurt if you look up.
- freezing rain: Rain that freezes upon contact with a surface. Stay away from these things
- The blowing snow: Snow blown more than 2.4 m into the air by the wind
- drifting snow: This is the same process as wind, but the snow remains below 2.4 meters. This also creates those neat wave-like drifts along the roads.
So don’t hibernate
Snow in winter can be a lot of fun. Why not bundle up and plan your next adventure?