How big can snowflakes get?
Snowflakes are agglomerates of many snow crystals. Most snowflakes are 1-1.5cm in diameter, however when atmospheric conditions are close to freezing point, winds are light and the atmosphere is unstable and significantly convective in nature, much larger (up to 5cm in diameter) and irregular snowflakes can prevail.
More information on snowflake size can be found in Chapter 1 of the PhD.
Why is snow white?
Snow is white, because its colour is related to its opaqueness, transparency and its ability to reflect sunlight. The colour of an opaque object depends on the frequencies of the light it reflects. The colour of a transparent object depends on the light that it transmits.
Snow reflects most of the visible wavelength from the sun because it is made up of countless reflecting crystals. This special combination of crystals gives snow its very white appearance as no absorption occurs.
Why do we build snowmen?
Snowmen were probably first made by people to scare away evil winter spirits. Today, however, they are built for fun.
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What is most famous snowman?
The most famous Snowman of all is 'Frosty', who appears in a Christmas song of the same name. The song was written in 1950 by Steve Nelson and Jack Rollins. The song was recorded in 1953 by Perry Como.
In 1969, a film called Frosty the Snowman was made. The story portrayed a magical snowman, who came to life and became best friends with a little girl. In the UK there is a film called 'The Snowman'. This snowman also comes to life and takes a little boy flying to see Father Christmas. The film is also associated with a famous song sung by Aled Jones (ex choir boy) called 'Walking in the Air'.
What is the largest snowman ever built?
The largest snowman in the world was made in Bethel, Maine U.S.A. on February 17th 1999. It was 35.5m high. It was called 'Angus' after Bethel's town mayor.
Is it ever too cold to snow?
No, it can snow even at exceptionally low temperatures. As long as moisture is present in some form in the atmosphere, snow can occur. However, the heaviest snowfalls due occur nearer to freezing point as warmer air can hold more water vapour at higher temperatures.
When is it too warm to snow?
Generally air temperatures at the ground up to 5-7°C may see snow reach the ground. The most important factor is that the atmosphere has a low wet bulb temperature, resulting in a low humidity to occur therefore allowing the snowflake to reach the ground without melting as the layer of atmosphere is relatively dry between the cloud and the ground. An alternative reason is that the snow partially melts creating evaporative cooling to take place around the snowflake, resulting in the atmospheric layer between the ground and the cloud to cool.
How do snowflakes form?
This question is answered in Chapter 1 of the PhD.
Why is snow a good insulator?
Fresh, undisturbed snow is composed of a high percentage of air trapped among the lattice structure of the accumulated snow crystals. Since the air within the snow crystals can barely move, heat transfer is greatly reduced. Fresh, undisturbed snow typically is 90-95% trapped air.
Is snow edible?
Clean pure fallen snow is certainly edible. Snow in urban areas may contain impurities like pollutants that one should not eat, however concentrations would probably be low, so risk to health is negligible.