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From reproductive rights to climate change to Big Tech, The Independent is on the ground when the story is developing. Whether it’s investigating the financials of Elon Musk’s pro-Trump PAC or producing our latest documentary, ‘The A Word’, which shines a light on the American women fighting for reproductive rights, we know how important it is to parse out the facts from the messaging.<\/p>\n
At such a critical moment in US history, we need reporters on the ground. Your donation allows us to keep sending journalists to speak to both sides of the story.<\/p>\n
The Independent is trusted by Americans across the entire political spectrum. And unlike many other quality news outlets, we choose not to lock Americans out of our reporting and analysis with paywalls. We believe quality journalism should be available to everyone, paid for by those who can afford it.<\/p>\n
Your support makes all the difference.<\/strong><\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\nRead more<\/span><\/svg><\/span><\/button><\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/aside>\n<\/div>\n<\/div>\nThe thought of snow can conjure up images of powdery slopes, days out of school or hours of shoveling. For millions of people, it\u2019s an inevitable part of life \u2013 but you may rarely stop to think about what made the snow.<\/p>\n
As a professor of atmospheric and planetary sciences, I\u2019ve studied how ice crystals floating in the sky become the snow that coats the ground.<\/p>\n
It all starts in the clouds.<\/p>\n
Clouds form when air near the Earth\u2019s surface rises. This happens when sunlight warms the ground and the air closest to it, just like the Sun can warm your face on a cold winter day.<\/p>\n
As the slightly warmer air rises, it cools \u2013 and the water vapor in that rising air condenses to form liquid water or water ice. From that, a cloud is born.<\/p>\n
Endless pathways<\/h2>\n<\/p>\n When temperatures are well below freezing on the ground, the clouds are primarily made of water in the form of ice. Under 32 degrees Fahrenheit \u2013 that\u2019s zero degrees Celsius \u2013 the frozen water molecules arrange themselves into a hexagonal, or six-sided, crystalline shape. As ice crystals grow and clump together, they become too heavy to stay aloft. With the help of gravity, they begin to fall back down through and eventually out of the cloud.<\/p>\n
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It takes approximately one hour for a snowflake to reach the ground (Getty\/iStock)<\/span><\/figcaption><\/figure>\n<\/div>\nWhat these ice crystals look like once they reach land depends on the temperature and humidity of the atmosphere. As the humidity \u2013 or the amount of water vapor in the cloud \u2013 increases, some of the ice crystals will grow intricate arms at their six corners. That branching process creates what we think of as the characteristic shapes of snowflakes.<\/p>\n
No two ice crystals take the same path through a cloud. Instead, every ice crystal experiences different temperatures and humidities as it travels through the cloud, whether going up or down. The ever-changing conditions, combined with the infinite number of paths the crystals could take, result in a unique growth history and crystalline shape for each and every snowflake. This is why you\u2019ve likely heard the saying, \u201cNo two snowflakes are exactly alike.\u201d<\/p>\n
Many times, these differences are visible to the naked eye; sometimes a microscope is required to tell them apart. Either way, scientists who study clouds and snow can examine a snowflake and ultimately understand the path it took through the cloud to land on your hand.<\/p>\n
Liquid water as glue<\/h2>\n<\/p>\n When snow falls from the sky, you don\u2019t usually see individual ice crystals, but rather clumps of crystals stuck together. One way ice crystals aggregate is through what\u2019s called mechanical interlocking. When ice crystals bump into each other, crystals with intricate branches and arms intertwine and stick to others.<\/p>\n
This mechanism is the main sticking process in cooler, drier conditions \u2013 what people call a \u201cdry snow.\u201d The result is a snow perfect for skiing, and easily picked up by the wind, but that won\u2019t hold together when formed into a snowball.<\/p>\n\nAbout the author<\/h2>\nAlexandria Johnson is a Professor of Atmospheric and Planetary Sciences at Purdue University.<\/p>\n
This article is republished from The Conversation under a Creative Commons license. Read the original article.<\/p>\n<\/figcaption><\/figure>\n
The second way to stick ice crystals together is to warm them up a bit. When ice crystals fall through a region of cloud or atmosphere where the temperature is slightly above freezing, the edges of the crystals start to melt. Just a tiny bit of liquid water allows ice crystals that bump into each other to stick together very efficiently, almost like glue.<\/p>\n
The result? Large clumps of ice crystals falling from the sky, what we call a \u201cwet snow\u201d \u2013 less than ideal for hitting the slopes but perfect for building a snowman.<\/p>\n
Snow formed in clouds typically reaches the ground only in winter. But almost all clouds, no matter the time of year or location, contain some ice. This is true even for clouds in warm tropical regions, because the atmosphere above us is much colder and can reach temperatures below freezing even on the warmest of days. In fact, scientists who study weather discovered that clouds containing ice produce more rain than those that don\u2019t contain any ice at all.<\/p>\n<\/div>\n","protected":false},"excerpt":{"rendered":"
Your support helps us to tell the story From reproductive rights to climate change to Big Tech, The Independent is on the ground when the story is developing. Whether it’s investigating the financials of Elon Musk’s pro-Trump PAC or producing our latest documentary, ‘The A Word’, which shines a light on the American women fighting for reproductive rights, we know how important it is to parse out the facts from the messaging. At such a critical moment in US history, we need reporters on the ground. Your donation allows us to keep sending journalists to speak to both sides of the story. The Independent is trusted by Americans across the entire political spectrum. And unlike many other quality news outlets, we choose not to lock Americans out of our reporting and analysis with paywalls. We believe quality journalism should be available to everyone, paid for by those who can afford it. Your support makes all the difference. Read more The thought of snow can conjure up images of powdery slopes, days out of school or hours of shoveling. For millions of people, it\u2019s an inevitable part of life \u2013 but you may rarely stop to think about what made the snow. As a professor of atmospheric and planetary sciences, I\u2019ve studied how ice crystals floating in the sky become the snow that coats the ground. It all starts in the clouds. Clouds form when air near the Earth\u2019s surface rises. This happens when sunlight warms the ground and the air closest to it, just like the Sun can warm your face on a cold winter day. As the slightly warmer air rises, it cools \u2013 and the water vapor in that rising air condenses to form liquid water or water ice. From that, a cloud is born. Endless pathways When temperatures are well below freezing on the ground, the clouds are primarily made of water in the form of ice. Under 32 degrees Fahrenheit \u2013 that\u2019s zero degrees Celsius \u2013 the frozen water molecules arrange themselves into a hexagonal, or six-sided, crystalline shape. As ice cry…<\/p>\n","protected":false},"author":1,"featured_media":8701,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[2],"tags":[],"acf":[],"_links":{"self":[{"href":"https:\/\/www.seekyourlove.com\/index.php?rest_route=\/wp\/v2\/posts\/8700"}],"collection":[{"href":"https:\/\/www.seekyourlove.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.seekyourlove.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.seekyourlove.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.seekyourlove.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=8700"}],"version-history":[{"count":0,"href":"https:\/\/www.seekyourlove.com\/index.php?rest_route=\/wp\/v2\/posts\/8700\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.seekyourlove.com\/index.php?rest_route=\/wp\/v2\/media\/8701"}],"wp:attachment":[{"href":"https:\/\/www.seekyourlove.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=8700"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.seekyourlove.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=8700"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.seekyourlove.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=8700"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}