Last Sunday, January 3rd we had a mixed bag event of rain, sleet, and snow. When the snow finally took over, the snowflakes were massive. Do you know why the snowflakes were so big? It is because the air aloft was slightly above the freezing mark. Because the air aloft was a bit warmer than the air at the surface it allowed some melting to happen. As snowflakes fall through air that is slightly above the freezing mark it partially melts. The water on the snowflakes acts as glue and when they bump into other snowflakes they become stuck together. This creates massive snowflakes.
An individual snow crystal has 6 sides and is quite small. If the air from the cloud to the ground is below 32 degrees the snowflake would be considered dry. Dry snow is made up of tiny snow crystals, and it is tough to make a snowball. If the air from the cloud to the ground has a few warmer spots (air above 32 degrees) then the snow will be considered wet. Wet snow is excellent for making snowballs.