Five Facts About Winter's Trademark: Snow

Updated: Mar 3

Snow is one of the most polarizing things about winter. People love snow or hate snow, but even people who love snow sometimes get sick of it.

Where snow falls, it is as essential as rain. Just like rain, snow helps us avoid droughts. In some parts of the western United States, melting snow provides more than 75% of the water supply.


Some plants and animals rely on snow and snowmelt for their survival. In the preserves, snowy winters are useful for planting seeds to sprout in spring. And many of our favorite winter activities — like sledding and skiing — require snow.


Whether you need a little help appreciating snow or just want to know more about one of the things that makes winter so special, here are five fun facts about snow.


It's not white


It turns out those rare years when we experience white Christmases are really just an optical illusion, because snow isn't actually white. Instead, snowflakes are colorless, or translucent.

 

Words to know


Contrary: Opposite in meaning.

Crystallize: When vapor or water solidifies into crystals.

Igloo: A dome-shaped shelter built of blocks of solid snow.

Inhospitable: An environment that is harsh or difficult to live in.

Insulator: A substance that does not readily allow the passage of heat or sound.

Minuscule: Extremely small.

Polarizing: Something that causes people to separate into opposing groups.

Prism: A transparent element that refracts light.

 

Snow looks white because the light reflecting off it scatters in many directions, which diffuses the color spectrum. That causes us to see it as white. This is similar to why we see the sky as blue. The sky reflects light too, but the blue wavelength of light is absorbed. With snow, no wavelengths of light are consistently absorbed or reflected because snowflakes are made up of so many tiny surfaces. Instead, the white light is what we see, so the snow looks white.


It can help keep you warm


It may seem contrary because it only snows when it is cold outside, but snow is actually a good insulator and can help keep you warm. Snow serves as an efficient insulator because it is between 90% and 95% trapped air. This means it can't transfer or move heat through it.


Its role as an insulator helps explain why some animals dig into the snow and burrow or shelter in or beneath it to hibernate or just to escape the harsh winter weather. It also explains why igloos, which are made entirely of snow, can be more than 100 degrees warmer than the air outside them.


In addition to being a good insulator of heat, snow is also a good absorber of sound. Have you ever noticed that the world seems more quiet after it snows? That's why. Snow is able to absorb most of the sound around it because it is so porous.


It's not unique to Earth


Earth is the only planet in the solar system with a climate that can sustain human life, but it's not the only planet where it rains or even snows. Even the most inhospitable planet in our solar system — Venus — has snow. Venus is the second closest planet to the sun, behind Mercury, but it is the hottest planet — with temperatures reaching as high as 860 degrees Fahrenheit. And yet there is snow on Venus.


The snow on Venus is probably more like frost than the snow we have here on Earth. And one more thing about the snow on Venus: It's made of metal. That's right; it's too cold on Venus for snow as we know it. The snow there is made of two different kinds of metal: bismuthinite and galena.


It snows on Mars too, although it falls to the ground so slowly — at a rate of about 1 centimeter a second — that it may mostly evaporate before reaching the surface. We don't fully understand the climate on any of the other planets, especially the more distant ones, but scientists believe it's possible the snow falls elsewhere in the solar system too, including Jupiter and Saturn's moons.


You probably can't even comprehend how many snowflakes fall each year


Even during snow droughts, a likely incomprehensible amount of snow falls each year. How much exactly? It obviously varies from year to year, but it's estimated that 1 septillion snowflakes fall from the sky each winter. You probably don't know what a septillion is, and that's understandable. It's hard to even fathom how much more a billion is than a million. One useful comparison: 1 million seconds amounts to about 11 days and 13 hours, while 1 billion second amounts to more than 31 1/2 years.


So then what's a septillion? A septillion is a 1 followed by 24 zeros, so it looks like this: 1,000,000,000,000,000,000,000,000. Another way to express 1 septillion is a trillion trillions.


Even the number of molecules in a single snowflake is impressive. While some snowflakes are very simple and have only about 10 molecules, the average snowflake contains 1,018 molecules of water. That's a lot of molecules in what looks like a very simple structure.


It's probably true that no two snowflakes are alike


Because of the sheer number of snowflakes that fall every winter — 1 septillion, remember — it would be nearly impossible to prove that no two snowflakes are identical. However, it’s likely true because of how snowflakes form and are influenced by atmospheric conditions.


Snowflakes start to form when water vapor condenses around a minuscule particle miles about Earth’s surface. These newly evolved particles then crystallize. These snowflakes or snow crystals are very sensitive to their microenvironments as they fall to the ground, which influences their appearance. It would be nearly impossible for two snowflakes to experience the same history of development, making it virtually impossible for snowflakes to be identical.


And although it's widely accepted by scientists that no two snowflakes are alike, that may only be true of the final product. At their earliest stages, snowflakes are simple, six-sided prisms. Most snowflakes will branch out, grow or merge with other flakes as they fall to the ground, creating nearly endless variations in shape, size and composition.

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