9781422272503

THE INSIDE SCOOP ON SNOW

It is never too cold to snow. At super frigid temperatures of -20°F (-29°C), it can still snow, but not much will fall. What is the perfect recipe for snow? The ingredients are moisture-saturated air, sufficient lifting of the saturated air into colder air to allow snow to develop, and an ambient temperature ideally above 15°F (-9.4°C). When these three ingredients are present, heavy snowfalls happen. Usually the air temperature near the ground is relatively warm. When temperatures drop below 15°F (-9.4°C), it is still cold enough to snow, but the air is generally too dry because the air capacity for holding water becomes minimal. Snow is not white. In fact, snow is translucent , and the light reflecting off it makes it appear white. The multiple crystals in the snowflake help scatter light in all directions, which diffuses the color spectrum so that only white is visible. Snow can be other colors as well. Dust and pollution in the air can cause snow to look dirty, and certain cryophilic freshwater algae can color snow blue, orange, or even black! For example, certain algae contain astaxanthin , a chemical which causes the

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