What Weston writes is true.
One of our iceboating friends, whose name I can't recall (Steve?), went through the ice by American Fork about 3-4 years ago, after sailing around for a while on what he deemed was good ice. He was pretty knowledgeable, so this entirely open spot took him completely by surprise. He was very lucky and was able to quickly clamber along the frame of his boat and mast and somehow get to ice that would support him, even as his boat sank to the bottom, with the 15-foot mast tip disappearing out of sight. (think about that image the next time you think Utah Lake is shallow)
He was luckily able to go out when the ice cleared and find it, but the important thing was that he didn't drown when it happened. Since that time I think 1 or 2 other persons have died in Utah Lake when going through the ice. One guy I think died even though he was wading back through breakable ice that wasn't over his head.
If you go -- consider getting some ice spikes, which are short hand grips with a spike on them that you can wear on you. They're used to pull yourself out of the ice once you've fallen through (think about how difficult it might be otherwise). We always have these with us when we go ice sailing (we used to make our own), although we always went when there wasn't snow and you'll probably go when there's lots of snow, which might help (or not!).
Cabela's web site has them:
http://www.cabelas.com/prod-1/0016930190554a.shtml Cheap insurance.
Good kiting!