Subject: How and where do whirlpools form in nature and how large large do they get?

I have searched your site, and the web extensively, and haven't 
found any answers, although I know more than I wish to know about 
washers and dryers. I want to know where I can see them, how they 
form, how big (and small) do they get, what kind of forces are 
involved and how much, where would a person go if he/she fell
into one. Also, could you explain how river hydraulics form, and 
how strong they are such as near a weir, as I canoe often, but 
never realized the dymanics of hydraulics, only the danger.

Re: How and where do whirlpools form in nature and how large large do they get?