NZ Weather Forum

This is a perfectly legitimate question (just trying to learn here!). I've seen more photographs of waterspouts in New Zealand than tornadoes, so my questions are:

a) Is this true, or merely more people live in the areas where waterspouts occur?
b) If true, why are waterspouts more common?
c) Is a waterspout simply a tornado over water? If so, why the heck do they happen just off shore and not on the land?

Thank you in advance for any answers, I would just google it, but I like to hear human responses.

Weetbicks wrote: c) Is a waterspout simply a tornado over water?

No, once a waterspout makes landfall it becomes a tornado.

I remember reading this in one of the tornado threads last year... it stuck in my head, and,
I never forgot it, ie: identifying the difference between the two - waterspout and tornado.

Maybe Vertigo, spwill, one of the weather guys can explain the technical side of it... meanwhile I'll go track that discussion down in the archives and see if I can pull the link up for you (not, now though I'm exhausted with holidays, children, brain tumours *bubbly laughter* ) I will post the link it before the week is over though...

*Yawns* scuse me... need to go.

a Yes, waterspouts are far more common than tornadoes.
b deep surface based instability is much more common over the sea than the land in NZ. (cold air over warm sea). Also, the waterspout process needs a surface boundary in light winds. This condition occurs more easily over the flat sea than the undulated land.
c Yes. But if you google you will get the American answer. They draw a distinction between the 'tornado process' (supercell) and 'waterspout process' (non supercell process common in coastal Florida/Great Lakes).

also, to add, i think also that a waterspout shows up more easily...i.e the condensation cloud....and is easy to see, unobstructed view usually.i.e there could be some landspouts that go undetected (behind a hill, un populated area, short lived,maybe?)

Also, waterspouts occur all year round where as landspouts are a warm season phenomena. I think Brians point about coastal waterspouts being more visual is a good point.

Also any sitings shown of waterspouts seems to occur even when its "fine/settled" wheres tornados seem to occur when theres a strong wind flow.

Adding on what NZStorm said.
Waterspouts can be classified as "a tornado over water" or just a general waterspout.
The difference is from the cloud type that it is made from.
If it came from a Thunderstorm i would say it came from a super cellular thunderstorm that contained a mesocyclone feature (the rotating updraft)- which is simply called a tornado over water (although weaker because its trying to pick up a heavy body of water)
Other wise if it doesn't come from a big cloud with an anvil on top, its just a general water spout.

Awesome, thank you for the replies everyone

Saw this waterspout a few years back off Aucklands Northshore, the towering Cu developed into Cb thunderstorm but the spout had gone by then which is usually the case.