I’ve ridden TB110 in heavy thunderstorms before. Because, like you said, I was out and despite the forecast of sunny skies, I am 10 miles (16km) from home and all of a sudden it’s a thunderstorm.
So while I would almost never choose to do it, it can be done, and with ease. You just have to act like you’re skating on ice. Don’t lean hardly at all and make big smooth arcs. And slow, go slow. Half normal speed. Less than half if it’s really bad. Don’t roll over wet leaves, or if you do, pretend they are kicking your back trucks out. Because they are 
It’s not an insurmountable problem.
Like driving a car in snow. Would most folks choose to drive in snow? F**K NO. But do they? Well, life doesn’t stop because it snowed. Cars drive in snow all the time. They do it real slow and careful. Thane on water is just the same.
Thane on snow, on the other hand, is something else entirely… and yes, it is very possible. Yes, it’s far, far worse than water.