Tuesday, February 23, 2016

Interesting Facts about Snow



Image Credit - feelgrafix.com
Snow falls when water vapor suspended in the air become ice crystals directly without first condensing into water. This happens when the temperature is below 0 degree Celsius or 32 degrees Fahrenheit.

How does snow form?

The formation of snow starts off with a tiny droplet of water freezing around a particle of dust in the clouds.  

The cold air freezes water vapor directly into ice crystals
when the temperature is below 0 degree Celsius or 32 degrees Fahrenheit.

Each ice crystal keeps growing in size as more water vapor turns into ice crystals and gets deposited.

When the ice crystals become very heavy due to deposition they fall to the ground as snow. 

After the snow falls to the ground, they remain as snow without melting if the temperature is cold enough.

According to the Guinness World Records, the largest snowflakes recorded were 15 inches in diameter and 8 inches thick. The record snowfall took place in eastern Montana on 28th January 1887.

Image Credit



Snowflakes in Different Shapes

What is a Snowflake?

Snowflakes are made of ice crystals. Each ice crystal joins with other ice crystals to form snowflakes. 

Each ice crystal varies in shape depending upon the temperature and water vapor content of the surrounding air.

Some of the most common shapes of snowflakes are are hexagonal prisms, needles, branching star like formations, branching fern formations, triangles, rimed crystals.

Temperature conditions and humidity can change the shape of the snowflakes.


What is lake-effect snow?

Lake-effect snow occurs when cold air passes over a warm body of water. 

When cold air passes over a warm body of water, the lower layers of air become warm and rises up into the cold air. 

As the warm air rises up into the cold air, the warm air  gets cooled and condenses to form ice crystals. These ice crystals grow in size and falls down as snow. This snow is called lake-effect snow.

What are hailstones?

Hailstones are pellets of ice that form when there is a strong upward movement of air during a thunderstorm. Hailstones can be small or can be as large as a golf ball. 

The formation of hail begins when the raindrop at the bottom of a thunderstorm cloud is blown upwards towards the top of the thundercloud by strong currents of wind blowing upwards. 

As the raindrop is blown upwards it freezes into ice as it enters freezing temperature. 

The frozen ice begins to fall again but the upward movement of air blows it upwards where it accumulates more frozen layers of ice and falls to the ground when it becomes too heavy for the air to blow it upwards.

The largest hailstone ever found was in Vivian, S.D., that weighed  1.9 pounds and measured 8 inches in diameter.

What is sleet?

Sleet is a type of precipitation that occurs during the winter season. In winter when the snowflake falls through warm layers of air it melts partially on the outside but the inner core remains frozen. 

As the partially melted snowflake falls it freezes again when it passes through layers of cold air and falls to the ground as tiny ice pellets or ice balls. Sleet melts quickly because the air above the ground is warmer and also because it does not have many frozen layers like the hailstones.


More about Snow

** Snow is colorless. It appears to be colored because it reflects the color of the dust particles or algae present in the snow.

** Heavy snowfalls are called snowstorms. 

** A blizzard is a snowstorm with freezing temperatures and winds blowing at high speeds.

** Fear of snow is called Chionophobia

** Average snowflake falls at a speed of 3.1 miles per hour

** Around 12 % of the earth’s surface on land is covered with permanent snow and ice.


** Snow reflects a high level of UV radiations that can cause snow blindness also known as photokeratitis. Sunglasses help to protect the eye from such radiations.


References

http://library.thinkquest.org/3876/snowfacts.html
http://www.toptenz.net/top-10-fascinating-facts-about-snow.php
http://www.learner.org/interactives/weather/iceandsnow.html
http://www.its.caltech.edu/~atomic/snowcrystals/class/class.htm

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