Snow: 9 strange but true facts

Snow is one of winter's most familiar sights and one of its strangest phenomena. If you have spent any time in Finland, you already know this in your bones. If you want to do something useful with that knowledge, here are five very Finnish ways to battle the winter blues. Snow will both cause them and, paradoxically, solve them.

1. Snow is clear, not white

Snow has no colour. Each individual ice crystal is transparent. The white appearance comes from the way light scatters across millions of tiny surfaces at once, bouncing between crystals and returning to your eye as a broad-spectrum blur. The same optical principle gives sea foam and cumulus clouds their colour.

This matters practically in photography. Snow photographs bright but flat, because it reflects so much light that cameras default to underexposure. Experienced photographers in Finland learn to dial in positive exposure compensation, or everything comes out looking grey and underlit. The snow is not overexposed. The camera is confused by something that does not have a true colour.

2. No two snowflakes are alike

Physicist Kenneth Libbrecht at Caltech has spent more of his career than most people spend on anything studying snowflake formation. His conclusion supports the old claim: true identical snowflakes are so vanishingly improbable as to be functionally impossible. Snowflakes form around a hexagonal ice lattice, which is why they have six-fold symmetry. No two flakes travel the same path through the atmosphere, so the combinations become astronomical.

3. Snow can be yellow or red

Yellow snow is avoided by social consensus in Finland as everywhere else. Red snow is stranger. It is caused by a green algae called Chlamydomonas nivalis, which contains a red carotenoid pigment. Cut into it and the snow smells faintly of watermelon. This is a recognised characteristic noted by researchers and hikers alike. Some organisms live in snow and have adapted to it fully.

4. Snow is not always cold to the touch

Snow is a surprisingly effective insulator. Still air trapped between ice crystals does most of the work. The thermal conductivity of fresh snow is roughly thirty times lower than solid ice. This is why animals survive under snowpack, and why humans have used snow shelters for millennia. Inside a well-built snow shelter, the temperature stays around zero Celsius regardless of how far below zero it is outside. Zero feels warm when it is minus twenty-five on the other side of the wall.

5. Snow can be extremely dry

Wet, heavy snow can contain twenty percent or more water by mass. Dry powder snow at cold temperatures can contain as little as two to three percent. Finnish winter, particularly in Lapland, produces some of the coldest and driest powder conditions in Europe. Tracks through dry Finnish powder collapse back slowly, which is why forest skiing routes stay readable for days after the last skier passed through.

6. Snow can be surprisingly heavy

A cubic metre of fresh dry snow weighs roughly fifty to one hundred kilograms. Wet settled snow can reach five hundred kilograms per cubic metre. Finnish building code accounts for snow load explicitly. Snow removal from roofs is a recognised task and, for commercial properties, a legal responsibility. Falling roof snow is classified as a liability risk. There are specialist companies in Finland that do nothing else. It is one of those practical Finnish winter adaptations that visitors from warmer climates find surprising, and that Finns who grew up here consider entirely normal.

7. The largest snowflake ever recorded

The record stands in Guinness World Records: a snowflake observed at Fort Keogh, Montana in January 1887, reported as fifteen inches across. The source is a single eyewitness account with no measurement instrument. Atmospheric physicists are sceptical. The 1887 account has never been retracted, and Guinness has never replaced it with a verified record. It sits in the books as the kind of historical claim that is impossible to disprove and impossible to confirm.

8. Thundersnow is real

Thundersnow is a convective snowstorm that produces lightning and thunder. The mechanics are essentially the same as a summer thunderstorm, but the storm is cold enough to produce snow rather than rain. Thunder in a snowstorm sounds different from summer thunder. The snow in the air absorbs sound more efficiently than rain, dampening the rumble and making it seem closer and more muffled.

9. Snow rollers form on their own

Snow rollers are hollow cylinders of snow that form without human involvement. Wind lifts a small piece of snow from the surface and rolls it forward. The conditions required are specific enough that most people never see one. When conditions align, fields can fill with dozens of them.

10. Snow actually quiets the world

Fresh snow absorbs sound. The porous structure of a new snowpack traps air in irregular spaces between crystals, and those spaces dissipate acoustic energy across a broad frequency range. Ambient noise levels drop noticeably after a heavy snowfall. A pine forest after overnight snowfall is quieter than it has any right to be. This is one of the less remarked-upon aspects of Finnish winter. The cold is discussed. The darkness is discussed. The quiet is taken for granted by people who grew up in it.

11. Snow has its own vocabulary

The Sami languages contain a well-documented range of specific terms for different snow conditions. Finnish itself distinguishes between lumi (snow generally), hanki (compacted snow crust), nuoska (wet, clinging snow) and several others. These are not poetic terms. They are functional ones. A language reflects what its speakers needed to describe quickly and accurately. In Finland, snow was infrastructure, terrain and seasonal calendar all at once.

Frequently asked questions about snow

Why does snow look white if it is actually clear?

Each ice crystal is transparent, but when millions of crystals are packed together, light scatters between them in all directions and returns to the eye as white. The same effect makes sea foam and clouds appear white.

Is it true that no two snowflakes are the same?

For complex, highly branched snowflakes, yes. The number of possible molecular arrangements across a full crystal is so large that identical structures are functionally impossible. Very simple early-season crystals are the exception, and can be nearly identical.

Can snow really be warm inside?

A snow shelter maintains an interior temperature close to zero Celsius even when outside temperatures are significantly colder. This is because snow is a poor conductor of heat. Zero Celsius is survivable. Minus twenty-five is not.

What is thundersnow?

Thundersnow is a winter convective storm that produces both snow and lightning. It forms the same way as a summer thunderstorm but in cold enough conditions to produce snow rather than rain. The thunder sounds shorter and more muffled because the snow absorbs sound.

What are snow rollers?

Snow rollers are hollow cylinders of snow formed naturally by wind under specific conditions: sticky surface snow, a slippery underlayer and moderate wind speed. They range from a few centimetres to over a metre across. They are rare enough that most people never see one in the wild.

101 Very Finnish Problems began as a list of observations about Finnish life. It became a book because the observations kept coming.

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