SNOWFLAKE NUMBERS
" It's been calculated that in a volume of snow two feet square by ten inches deep there are
roughly one million flakes.
Multiply that by the millions of square miles that are covered by snow each year (nearly one
fourth of the earth's land surface), and then multiply that by the billions of winters that have
occurred since the dawn of time, and it's obvious we're talking unimaginable googols of
flakes. Some of these are surely repeats.

On the other hand, a single snow crystal contains perhaps 100 million molecules, which
can be arranged in a gigajillion different ways".

source:http://www.straightdope.com/classics/a3_392.html