Ice weakens as it nears the coast, because every day, particularly in the summer, enormous walls of ice flake off the glacier and fall into the ocean. Snow that started as flakes was transformed to dense glacial ice as it moved quickly, about four miles per year, toward the west coast of Greenland. With time, the fresh flakes descended into the ice, hidden from daylight, and compressed by pressure to a third of their original size.įitting with geology, thousands of years passed and little happened. The landmass was already covered in ice two miles thick. It was probably this form of fern‐like snow that fell one day, fifteen thousand years ago, on the frozen ice sheets of Greenland. Extra‐cold weather is when you find the classic shape of a six‐sided prism, or the fern‐like crystal with six radiating branches. Cold temperatures produce flakes that look like bullets or needles. They start as spheres and form tendrils to diffuse heat. And even though every snowflake is different, they’re not as unique as we’ve been told. Snow tends to fall in places where other snow has already fallen.
But as soon as one extra crystal crosses the tipping point, the structure will succumb to gravity and fall. As long as the growing snowflake remains lighter than air, it will float. A piece of dust forms a crystal, and the appearance of that crystal attracts more crystals until they form long dendrites around the speck of dust like ants around a piece of chocolate. When snow falls, the properties of water perform a delicate dance.
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