Spontaneous Funnel Cloud

I saw a spontaneous funnel cloud yesterday. I suppose it is technically just a whirlwind, not a tornado, as apparently a tornado has to be connected to the cloud and the ground. To me, this was really cool. It would be cool to see a tornado for sure, but to see something that I had never even heard of was pretty cool as well.

We were driving along and I thought I saw smoke over the tree line, but it looked funny. It was as white as the clouds, which you normally only see if they are putting out a fire and you have steam instead of smoke, but there was no darker smoke above it from the pre-watered fire. Also, the smoke column appeared to be getting taller faster than it was rising. As we watched, it thickened and then suddenly tightened into a very distinct column just like a tornado, only it was white (which I suppose a normal tornado probably would be if it was out in the daylight instead of under a thundercloud). As far as I could tell, it wasn't connected to any cloud. And with the trees in the way, I couldn't say for sure whether it touched the ground or not. As to height, the visible column was at least 5 or 6 times the height of the trees in front of it.

The day wasn't clear. The sky was spotted with clouds, so an invisible vortex could have been associated with a cloud above. I think the original "smoke" was probably condensation from the pressure change as the vortex began forming. If that is the case, I would have expected it to be visible up to the cloud if it was connected, since a cloud would be direct evidence of enough moisture to become visible in the first place, but maybe not.

After doing research, the closest thing I could come up with is a "cold-air funnel cloud", which is pictured at right from wikipedia. The one I saw, as I said, wasn't attached to a cloud, and it was much more well defined, with a smoother margin, at least to me. I haven't found any images without the column being attached to a cloud, but I'm still looking. Surely someone else has seen one.

I wish I had gotten a picture, but the thing only lasted a few seconds. It had almost totally dissipated (there was still some high-level fluff left) 10 or 15 seconds after the column formed, so I wouldn't have gotten a picture even if I had had my camera with me. But trust me, it was still cool.