M.E., on 06 October 2017 - 04:18 AM, said:
I think they are so cool.
So, does it only happen over large bodies of water?
There are actually several distinct types (mechanisms of formation)
A Tornadic Waterspout happens when a "land tornado" passes over or touches down on any water. I've heard TV meteorologists in the US southwest say that this is "what a waterspout is". Well, maybe for them!
The more common kind of waterspout, "fair weather spout" occurs over warm waters. Optimal
surface temp seems to be around 30C/85F, but it can happen in cooler waters. These aren't associated with thunderstorms, and associated with some sort of cumulus cloud (aka "the fluffy type"), often with a flat bottom. I'll spare you the physics: I've exhausted my month's allotment of rants about latent heat of vaporization, etc. (*sigh* someday. I'll get to the end of the month!). It takes some form of crosswind or current to set the quickly rising, slowly cooling, moist air spinning, and "tighten" it into a water spout. Nonetheless, these are quite common: each year, there are more waterspouts in US southeast coastal waters than tornados of all kinds in Tornado Alley
I've seen current
public information films/documents from organizations like NOAA, The Weather Channel, etc. claiming that these are the only two types of waterspouts. But if you get real
chummy with meteorology researchers (and really, why would anyone not?), you'll eventually find out that's just what The Powers The Be want you to think!
For example, there have been waterspouts in/around Antarctica, where the water is frigid (surface temps can be below 0C/32F, because it's salt water). No tornado has ever been seen/detected in Antarctica.
I also feel that there are sufficient differences in the mechanism of Great Lakes "lake effects spouts" to call them a separate class: no tropical water and no thunderstorm/tornado.
I could list out several other less-common types, but I want to leave you with this: the extremely rare Lava Steam-vortex waterspout. (Yeah, my mental world is a house of horrors)
Copyright: Bruce Amori/Extreme Exposure