WHAT CAUSES GIANT SNOWFLAKES?
METEOROLOGIST JEFF HABY
An individual snow crystal has 6 sides and is very small. A snowflake is composed of several of
these 6 sided crystals.
Whether snow is more dry or more wet depends on the
snow to liquid equivalent. When the temperature
throughout the troposphere is well below freezing the snow is term a "dry snow". A dry snow
has little to no liquid within the snowflakes. During a dry snow, snowflakes tend to be smaller. Also, when
trying to make a snowball, it falls apart for the most part.
In a situation in which part of the troposphere is very near or just above freezing, the snowflake will partially
melt. This produces a liquid film on the snowflake. This makes it much easier for snowflakes to stick
together. Thus, it is liquid water that is the "glue" to producing large snowflakes and snow that is
easy to make snowballs with. While a dry heavy snow tends to have a huge amount of small snowflakes,
wet snow tends to have a smaller number of snowflakes but the
individual snowflakes are large.
While a raindrop has a theoretical size it can grow to before breaking, the limit to the maximum size of a
snowflake is less defined. In a heavy wet snow situation in which the winds are light, snowflakes can grow
to silver dollar size diameter or larger. This situation can look like little snowballs falling from the sky.
Light wind prevents the snowflakes from breaking into pieces and the liquid film around each snowflake
helps them stick and accrete to surrounding snowflakes as they fall.
It is difficult to determine what the largest snowflakes to have fallen are since the snowflake splashes into a
pool of snow as it hits the ground. Eyewitness accounts are the main source of information. Some have
reported snowflake complexes to the size of baseballs or larger but many of these reports
are difficult to verify.
The ultimate weather education website: http://www.theweatherprediction.com/