Light hitting the snow reflects in all directions, so the light that reaches our eyes from the snow has been reflected many times from the individual flakes. This means that what we see when we look at snow is actually a mixture of all the colours in the spectrum. In addition, each flake reflects different wavelengths and absorbs others, so what we see as white is a mixture of all colours.
So, the colour of snow depends on the size, shape and arrangement of the individual crystals. Snowflakes are made of ice crystals. The tiny hexagonal prisms that make up a snowflake refract light, which means they bend it in different directions. The light coming from all sides of a single hexagon is bent so that it looks white from all angles.
Snowflakes can be any shape and size, but most are small and flat. They have six sides: two faces, two edges and two corners. The corners act like little mirrors to reflect light onto themselves and make the whole flake appear white when viewed from almost any angle.
Why is Snow White Even at Night?
The answer lies in the way light is reflected off the snow.
However, the colour of snow is a subject that has intrigued scientists for years. It turns out that there are several reasons for this, and the answer depends on where you live and when you are observing it.
In fact, snow can appear to be white at night because of the way your eyes perceive colour. Human eyes contain three types of light receptors called cone cells. They each come in two varieties, one sensitive to short wavelengths (blue) and one to long wavelengths (yellow). The third type is sensitive to the green light at around 550 nanometres.
The main function of these cones is to help us see colours, but they also help us see in low light levels by helping our brains create an image from the millions of photons entering our eyes at any moment. So, the fact snow is one of the most reflective substances on Earth. It is so reflective that it actually reflects away most of the sunlight that hits it.
At night, there isn’t much light coming from above to reflect back at us, so snow looks like a uniform shade of white — even though its real colour in daylight is blueish white.
Common Properties of Snow
If you have ever been to a cold climate or mountainous region, then you might have seen snowflakes falling from the sky. You might have also experienced how cold it feels when these tiny water droplets fall on your face or hands.
If you have never noticed anything about the snow or haven’t been to any snowing place, here is how snow gets categorized according to its properties.
The depth of snow is the amount of snow on the ground at any given time. This depth is measured from the ground surface to the top of the snowpack. It is typically measured in inches or centimetres, but some ski resorts may use feet as a unit.
The density of snow depends on its water content (snow water equivalence), the temperature, and how tightly packed it is (known as compaction). Snow can range from loose powder (low density) to hard-packed powder (high density). The more compact a layer of snow is, the denser it will be because there are fewer voids between individual crystals.
Snow Water Equivalence (SWE)
Snow water equivalence (SWE) is the amount of water that would result if all the snow on the ground melted at once. This value can be estimated by adding up the depths of each layer individually and then dividing by their respective density values.
White Snow Movement Mechanism
The snow movement mechanism in a white snowflake differs from that of an ice crystal. So, there are many types of snow movement mechanisms, including:
Avalanches are masses of snow that slide down a mountain. They can be caused by earthquakes, explosions, or other disturbances. Avalanches also occur when the snow is too heavy for the surface to support it. Instead, the weight of the snow pushes down on the surface, causing cracks to form in the snow below. These cracks widen as more and more weight is placed on them until they break completely through and slide downhill.
Snow slides are similar to avalanches but occur on gentler slopes with less weight behind them. As a result, they may move slowly or quickly depending on how much weight they carry and how steep the slope is. Snow slides usually start at a crack in the surface and spread outwards like an avalanche would if it were moving faster than usual.
A glacier is a large mass of ice moving slowly over time. Glaciers are found at high altitudes in polar regions and on some high mountains in temperate regions around Earth’s globe. Glaciers form when accumulated snow stays frozen throughout summer for multiple years. Over time, glaciers expand into valleys and create deep U-shaped troughs called glacial valleys (or cirques) by damming up streams and rivers with ice, then eroding that ice with their weight until only the hard rock remains exposed above ground level.
Drifting is when a layer of snow detaches from the ground and moves horizontally. This process occurs when a layer of snow on top of a hard and icy surface melts into water and freezes back into ice. When this ice freezes and repeatedly melts over time, it results in a layer becoming detached from the hard surface below it. The weight of this layer can cause it to move across the surface as it drifts.
This type of movement is most common during thaws or nighttime hours when temperatures are above freezing but still below freezing at night. This allows for melting to occur during the day and freezing at night, sometimes resulting in layers being pushed across surfaces by the wind.
How Does Snow Fall from the Sky
The process of snow falling from the sky begins with the formation of clouds. Clouds are made up of water droplets that have frozen into ice crystals. These ice crystals can be of many different sizes — from tiny microscopic particles to large snowflakes that fall from the sky.
The water droplets in clouds freeze when they come into contact with tiny particles in the air (such as dust, soot and salt). This freezing process causes them to become more compact and form ice crystals. As more water droplets freeze onto these crystals, they become larger and heavier until they eventually fall out of the sky like snowflakes.
Most clouds are found at high altitudes — anywhere between 7 km (4 miles) above sea level and 10 km (6 miles) above sea level. This means that most clouds are extremely cold temperatures, ranging from -40°C (-40°F) to -60°C (-76°F). It’s not uncommon for temperatures within these clouds to fall below -50°C (-58°F), which is why it’s so hard for snowflakes to reach Earth’s surface. Snow is a form of frozen precipitation that falls from clouds. The small ice crystals that makeup snowflakes are carried by the wind in clouds and then fall to the Earth when they reach temperatures below freezing. Snow crystals can be formed in many different shapes, but the most common shape for snowflakes is a six-sided star.