I've seen several waterspouts over the years on Lake Ontario and there's a number of Youtube videos showing them here as well. While typically not as strong as a land tornado, they can ruin your day and are to be respected. They seem to be more prevalent some years than others, and it seems like there may be more this year than other years recently. They occur when the water is warm but the air is cool and unstable. Any horizontal circulation in the air flow can start winding them up in these conditions.
Here's an interesting video of a waterspout toying with a large ship . . . Singapore Waterspout Plays With Boat - YouTube