[AllenG (OP)]

If it is below freezing it should all be solid.
So what makes some snow wet and heavy and other snows dry and fluffy?

[litespeed]

You have come to the right place!  It has entirely due to the temperature. For instance, snow that falls in zero degrees F will not only be fluffy and dry, it will actually sqweek when walked on.  Wet snow falls in much warmer weather.

For instance, back 'in the day' we would get very wet Ohio snow in April. Snow can fall with air temperatures as high as 40F surface temperatures. That means the atmosphere [though cold enough to form snow] can hold much larger amounts of moisture that freezes into larger flakes that also clump together.

These big flakes then fall into the warmer lower atmosphere where they begin to slowly melt.  Jeeze. We could get ten inches of the stuff. You could get a hernia trying to shovel it.  As kids, we make snow balls and roll them down hill. These would accumulate the entire surface snow into gigantic balls four feet or more tall.  We would roll several of them into a single place and tunnel out magnifficant snow forts. Lucky none of them collapsed on us.

You can not roll large snow balls in cold temperatures since it will not stick together. As kids, we knew the 'window' for really good wet snow fort snow depended on three things. 1) Temperature; 2) Available sunshine; and 3) Wind. On a calm sunny day we might get wet snow with temperatures as low as 28 degrees. A cloudy day with a bit of wind chill might provide wet snow into the upper thirties before it turned to unusable slush.. 

[AllenG (OP)]

Thanks Lightspeed