Q and A about snow

Question: Why is snow white?

Answer: Visible sunlight is white. Because of the countless tiny surfaces contained in the complex structure of snow, most visible light is reflected back.

Question: Is is ever too cold to snow?

Answer: No. It can snow at incredibly low temperatures, provided there is a source of moisture and some way to lift or cool the air. However, most heavy snowfalls occur with relatively warm air temperatures near the ground — typically 15 degrees F or higher, since air can hold more water vapor at higher temperatures.

Question: Is snow edible?

Answer: Clean snow is edible. Snow in urban areas may contain pollutants that one should not eat, but they are probably in such low concentrations that it wouldn't matter. However, eating snow should be confined to wilderness areas.

Question: Why do weather forecasters seem to have so much trouble forecasting snow?

Answer: Snow forecasts are better than they used to be, but snow forecasting remains one of the more difficult challenges. One reason is that for many of the more intense snows, the heaviest snow amounts fall in narrow bands. Also, extremely small temperature differences that define the boundary line between rain and snow make big differences in snow forecasts.

Question: Why does snow crunch when you step on it?

Answer: A layer of snow is simply composed of ice grains with air in between. Because the snow layer is mostly empty air space, when you step on it, you compress the layer. As snow compresses, the ice grains rub against each other. This creates friction or resistance. The sudden squashing of the snow at lower temperatures produces the familiar creaking or crunching sound. The colder the snow, the louder the crunch.

Question: Is there 1 inch of water in every 10 inches of snow that falls?

Answer: The water content of snow varies more than most people realize. While many snows that fall at temperatures close to 32 degrees F and snows accompanied by strong winds do contain about an inch of water per 10 inches of snowfall, the ratio is not generally accurate for most of the United States. The ratio can vary from as low as 1 inch of water in 100 inches of snow to as high as one inch of water in 3 inches of snow, depending on crystal structure, wind speed, temperatures and other factors.