Now that winter is fully upon us and snow is covering ground across portions of the United States, it's time to answer the question, what is snow? This is also a question that many parents are likely to get from their kids this winter. Therefore, it's important to know the correct answer. So, what is snow?
Snow is not simply frozen rain. Frozen rain is ice, so snow is a bit different. Similar to rain, snow starts as water vapor in our atmosphere. If it is cold enough, the water vapor can turn into an ice crystal. A combination of ice crystals gives you a snowflake.
You've probably also heard that no two snowflakes are alike. For the most part this is correct. The chances of observing two snowflakes exactly alike are so rare that there are more snowflake possibilities than the number of snowflakes that have fallen across the globe over the history of all mankind. It's not impossible to find two snowflakes exactly alike, but it is extremely unlikely. So unlikely that no one has ever found 2 exactly alike.
Here's a great site that explains snowflake probability.