[Geezer (OP)]

There certainly seem to be different types of snow. Sometimes, when it's on the ground, it's very light and fluffy, and other times it's really heavy and hard to move around.

People talk about "wet" snow and "dry" snow, but when snow is falling, can it really be wet? After all, it's really just ice crystals. If it was wet, it wouldn't be snow at all, it would be rain.

What's going on here?

[CliffordK]

YES...

I'm from the Willamette Valley in Oregon...  It usually snows at about 32°F (0°C).  Sometimes even slightly above freezing.  High humidity...  It is just WET. 

It is EASY to make snowballs.

I spent a couple of years in St. Louis.  The most frustrating thing that it is almost impossible to make a snowman.  The snow is just too dry.  It doesn't stick together, and falls apart.  Sometimes one can wait until just before it melts for it to become sticky enough to make a snowman.

[Geezer (OP)]

Thanks Clifford!

That's reminds me that where I grew up, you could literally roll the snow up leaving a path on the grass that had no snow on it at all. We could make snow rolls up to a maximum of about four feet in diameter.

[cat_with_no_eyes]

If its white stuff then its snow, no matter whatever you say.

[CliffordK]

That's reminds me that where I grew up, you could literally roll the snow up leaving a path on the grass that had no snow on it at all. We could make snow rolls up to a maximum of about four feet in diameter.

Exactly...
Not very scientific, but let's call it the snowman test for wetness of snow.  And, you can't easily roll a snowman in St. Louis.

It probably has more to do with temperature hovering around freezing, and humidity & dewpoint than anything else.

[SteveFish]

You are leaving out two very important tests that I learned in Northeast Ohio. 1) The squeak test. Cold dry snow squeaks when you walk on it. 2) The nose hair test. When you step outside and you can feel your nose hairs stiffening from the well below freezing air, the snow is going to be dry.

[Geezer (OP)]

Thanks all!

My question was really more to do with the state of the snow before it hits the ground. Maybe I should have asked something like  - Are some snow crystals "wetter" than others?

[SteveFish]

Geezer, because it is usually colder up high where the snow crystals form, it seems likely that they might melt partially as they fall through warmer lower altitudes, especially when the overall temperature is not very cold. I don't know. Steve

[Geezer (OP)]

Thanks Steve.

I suppose the ice crystals are colder when the ambient temperature is lower, so it will take a bit more heat to cause them to melt, but I think that would be a rather small effect compared to the total amount of heat required to convert them into water. Of course, there could be some partial melting as the snow falls, but then I think it would look a lot more like sleet than snow.

I'm inclined to think the "wetness" is more a consequence of the conditions at, or close to, the ground, but then again, there are very different types of snowflakes.

This must be a subject worthy of a large scientific research grant.

 

[CliffordK]

I'm inclined to think the "wetness" is more a consequence of the conditions at, or close to, the ground, but then again, there are very different types of snowflakes.

Exactly...  If it is 31°F to 33°F, -1°C to +1°C, at ground level, and near the dew point...  the snow will be wet.

What about the "Windshield Test".
There is a point between rain, sleet, and snow where the snow flakes hit the windshield and make star-like droplets of water, without a trace of ice. 
Only when it gets a little colder and dryer, will the snow flakes impact the windshield and remain partly or wholly frozen.

I wonder if there are differences in the sizes of snowflakes. 
I know that in Oregon, sometimes near freezing we can get some huge, floating snowflakes... Perhaps an inch in diameter.  And it might not even be cold enough to stick.

[Geezer (OP)]

 
I know that in Oregon, sometimes near freezing we can get some huge, floating snowflakes... Perhaps an inch in diameter.  And it might not even be cold enough to stick.

Yes - I saw some like that the other day. It was fairly warm at the time, and the snow on the ground did seem to be rather "wet". I always assumed those big flakes were multiple crystals that had somehow clumped together, but maybe it's more to do with humidity promoting the growth of large crystals.

Obviously, need our resident snowflakeologist to chime in on this one.

[SteveFish]

I have found that snowflakeologists are self described flakes driven as if by an emotional winter storm of obsessive compulsive desire to record every possible ice crystal pattern that might be possible. Otherwise they are pretty laid back.

[Geezer (OP)]

I have found that snowflakeologists are self described flakes driven as if by an emotional winter storm of obsessive compulsive desire to record every possible ice crystal pattern that might be possible. Otherwise they are pretty laid back.

I dunno aboot that Steve, but they sound just a wee bit flakey, if you know what I mean.