What should I expect in winter while visiting Venice? Will it flood?
I'm pretty sure the aqua alta peaks in November. They aren't really floods anyway, usually it's just a minor annoyance to work arround (and only in the morning hours).
This news article tells about the Venice floods of December 2008.
Rick's information is that, on average, there's some flooding in Venice about 100 times a year. Flooding is more frequent in November and March.
Flooding there occurs when winds blowing from the south (Egypt) combine with high barometric pressure over the southern Adriatic Sea to push the sea water toward the sea's northern end (where Venice is).
Even if it does flood, it's usually not as disruptive as the December 2008 flood, and doesn't need to ruin your entire Venice trip.
But if it does happen when you're there, it can become a factor that both locals and visitors have to workaround and adapt to. The flooding causes the crowds in certain areas to be worse, because people cluster on benches put down for the flood or in other places where the water isn't so deep.
And the market price of Wellington style rubber boots will go through the ceiling!