Everyone knows what snow looks like. But did you know that it can scream, is actually black and has become an art genre in its own right? Snow is a fascinating thing. Wherever it falls, snow changes the landscape and the environment – but snow itself is also very changeable. We humans have been fascinated by the fluffy white stuff for centuries. Here are 22 facts about snow.
01 · Snow is not frozen rain
Snowflakes are formed directly from water vapour in the clouds. They skip the liquid state, so to speak. Snowflakes form their typical shape – with six perfectly symmetrical arms – as they fall to the ground, crossing different temperature and humidity zones on the way.
02 · Snow is white and black
Snowflakes have many tiny branches and twisted surfaces which refract light in different directions. The individual rays of light overlap, meaning that what we see is white. However, if we look at the so-called thermal spectral range, snow is actually black: it absorbs almost one hundred percent of thermal radiation.
03 · Each snowflake is unique – but only in theory
So far, no two snowflakes have been discovered that are completely identical. An ice crystal with a diameter of just one millimetre has around 100 trillion water molecules. The probability that all molecules are in the same place in two flakes is therefore tiny – but not impossible. It has been proven that snowflakes form a variety of shapes, though as a rule they always have six corners.
04 · Snow is loud
Snowfall can be heard. How loud it is depends on its intensity and the wind force. Quiet snowfall is usually estimated at around ten decibels, which is the volume of normal breathing. As snow falls, the surrounding environment gets quieter. This is because ambient sound is absorbed by the snow crystals.
05 · Snow screams
According to Canadian researchers, snowflakes make a shrill sound when they land on water. This is because the flakes contain small air bubbles. When they are released, they produce sounds at a frequency between 50 and 200 kilohertz – inaudible for humans.
06 · Nobody knows why snow and ice are slippery
It is still not entirely clear why ice is good for skating and snow for skiing. It used to be thought that the ski exerts so much pressure on the snow that it causes the top layer to melt. However, this pressure melting theory has been disproved. The theory of frictional melting is more likely. But why do we feel like we are slipping very slightly even when standing still on skates or skis? Every layer of snow or ice has a very thin layer of water on its surface, whose sliding effect is intensified by different types of melting.
07 · The Inuit do not have 200 words for snow
It is not true that the indigenous people of the Arctic have a particularly large number of terms for snow. Their language is structured quite differently than German or English. Individual words are often difficult to pin down and depend on the context. German, in fact, is a language with many terms for snow. Experts use different terms depending on how much water it contains (“Pulverschnee”, “Pappschnee”, “Faulschnee”), how old it is (“Neuschnee”, “Harsch”, “Büßerschnee”) and how dense it is (“Schwimmschnee”, “Firn”, “Eis”).
08 · Snow is a dirty business
Without so-called crystallisation nuclei, snowflakes cannot form in the clouds. These nuclei can be dust or pollen particles, for example. Droplets freeze on them and, at the same time, the air around the particles and droplets also freezes.
09 · Natural snow is the almost perfect building material
First, snow is 100% sustainable. Second, snow is a poor conductor of heat – air is trapped between the ice crystals, creating an insulating effect. Third, snow which is slightly thawed becomes hard as concrete over time and seals well. This is why Inuit build breathing holes in their igloos. In fact, the biggest downside of snow as a building material is simply the temperature – if it gets too warm, snow melts away rapidly.
Source: Charlie English: The Book of Snow
10 · The smell of snow
Snow is water and therefore odourless. Nevertheless some people are convinced that they can smell snow. One explanation is that snowflakes contain aerosols or algae that have an inherent odour. Another is that snow prevents odours from rising from the ground, making the air “smell” unusually clean – creating what we call the smell of snow.
11 · Snow is a weapon
Snow has played a role in many wars. In the 8th century, peasants in Norway defeated a Viking prince because they were able to move better on skis through the snowy landscape. Around the year 1200, “ski soldiers” were deployed for the first time in Scandinavia. On 13 December 1916, thousands of soldiers were killed by an avalanche in the Southern Alps. Indeed, during the First World War it was not uncommon for avalanches to be triggered on purpose in order to bury enemy troops. Last but not least, both Napoleon and Adolf Hitler lost tens of thousands of men to the snows of the Russian winter.
12 · The “snow effect” only exists in art
Painters love snow. The Impressionists of the 19th century captured the snow-covered landscapes on canvas during a phase today called the “Effet de Neige” (“snow effect”). Japanese artists even tried to imitate snow’s different shades of colour and light by layering several prints one on top of the other.
13 · You don’t need snow cannons to make artificial snow
In old Hollywood movies, directors would use cornflakes dyed white to create the effect of snow. Unfortunately, these flakes were sometimes so loud that scenes had to be dubbed. Today the movie industry uses “real” artificial snow, though it is produced chemically and not using snow cannons – a process which results in very high levels of emissions. In some cases this fake snow for TV and films can reach depths of up to 10cm.
14 · The snow globe is an Austrian invention
The Viennese toolmaker Erwin Perzy opened the first factory for “glass balls with snow effect” in 1900. He had actually wanted to create a new lamp, but the metal shavings swirling around in the water reminded him of snow – and so he ended up making the first snow globe.
15 · Snow can be more than one colour
In the Middle Ages, red “blood snow” was considered a bad omen. There are two explanations for this rare phenomenon. It can happen when Sahara dust in the air becomes trapped in snowflakes. Certain types of algae can also dye snow red or green. And when it comes to yellow snow, it’s probably best to stay away!
16 · Snow and unborn children can be measured in the same way
These days it is common to use ultrasound to measure snow depths. The depth can be determined by measuring how long it takes sound to travel through the snow. To ensure that the measurement is accurate, however, the sensor needs additional information, for example on air temperature.
17 · Snow is heavy
A single snowflake weighs on average 0.004 grammes. However, snowflakes are never an individual phenomenon – they come in masses. One cubic metre of dry powder snow weighs between 30 and 50 kilos. If it gets wet and compacts, snow can weigh up to half a tonne per cubic metre. A layer of ice only 12 centimetres thick weighs as much as two to three metres of fresh snow.
18 · Snow moves very slowly
Because individual snowflakes are so light, they take a long time to fall. Without any wind, snowflakes travel at about four kilometres per hour. Even if the flake grows as it falls, i.e. becomes heavier, that hardly matters: the increased surface area slows its descent.
19 · Snow makes you blind
Due to its structure, snow reflects a huge amount of sunlight. Without protection, the eye’s cornea and conjunctiva can be burnt – similar to sunburn on the skin. The resulting phenomenon of snow blindness (known in medical parlance as actinic keratosis and photokeratitis) can result in a painful loss of vision.
20 · Snowflakes can become huge
The largest snowflake ever recorded is said to have measured 38 centimetres in diameter. Unfortunately there is no way of verifying this report from 1887. What is certain, however, is that snowflakes can grow very large by clumping together – according to meteorological studies, as much as 10-20 centimetres in diameter.
21 · Snowflakes are not always perfect
In photos, snowflakes with their many intricate branches appear perfect. But in fact, just 275 water molecules are sufficient to form a snowflake – a much more basic construction than the works of art we are used to seeing. As temperatures rise, snowflakes become larger and less symmetrical.
22 · It even snows on Mars
Astronomers believe snowstorms are a regular occurrence on the Red Planet, though the snow probably evaporates before it reaches the ground. Mars is, however, home to huge glaciers – the Korolev Crater, for example, is more than 84 kilometres in diameter and is covered by an ice sheet 1.8 kilometres thick.