Even with all of our fancy technology, snow is still hard to predict and measure; but what knowledge we do know I'll try to pass on here. See Snowflake for a more in-depth description on the flakes themselves.

Snow is a general term referring to a conglameration of Snowflakes, either resting on the ground, falling from the sky, or crunched up into a ball. It is also the name of a musical artist (quite the flake indeed) and the title of countless poems.

High density snow is referred to as Firn if it is older than one year old; see the Firn node for specifics on that topic (thanks, ailie).

It has been (falsely) reported that Eskimos have one hundred names for snow - but you can easily see why when skiers started bringing new names for snow into popular culture. Some of the more frequently heard ones are "fluffy snow," "powder snow," and "sticky snow." As things needed a bit more clarification, even more terms came up; including "champagne powder," "corduroy," (snow groomed into hard ridges) and "mashed potatoes."

Did you know that snow is an excellent insulator? Well it is! "Ten inches of fresh snow with a density of 0.07 inches, seven percent water, is approximately equal to a six-inch-layer of fiberglass insulation with an insulation R-value of R-18." - source: nsdic.org

As beautiful as it is, snow kills thousands of people per year. The "most popular" ways to die due to the winter wonderland are from traffic accidents, overexertion, and exposure. Only recently have avalanche deaths been a more popular option, probably due to the increase in expeditions and climbing excursions, extreme winter sports, and just the general increase in population.

Weirdness: The greatest snowfall reported in Phoenix, Arizona was one inch. One measly little inch. It happened twice, even! The first time was January 20, 1933, and the second time it happened again four years later on the same date.

Sources: nsidc.org, meteorology class, caltech.edu.