I had my first crash on the fat bike today. I was riding home along the railroad bed and there is a portion that is flooded/frozen over. I've ridden over it several times without incident and perhaps I got a bit too comfortable. The bike came out from under me then the machine and I slid forward. I don't have studded tires right now, but check out what you could do with studded tires in this video below.
Clarity: An Ice Biking Session from Aaron Peterson Photography on Vimeo.