Flotation tires come in very large sizes and can accommodate a lot of air. As a result, they can flow over the surface, which can be helpful when driving on sand or over large rocks.
However, it's not that simple with snow. Namely, to get traction in snow, you'll want a narrower tire that can penetrate and do some digging action and keep your SUV or truck stable laterally. Of course, the tread compound and design also play a big role – a winter tire will always give the best results – but generally, a narrower tire will work better.
Interestingly, that's not always the case. If you drive over very deep snow, like the type you encounter when driving in some Northern areas – Canada and Alaska are the first that come to mind – flotation tires will work better. In this case, narrow tires could sink too deep into the snow, and you might get stuck.
So, if you need a set of tires for some Arctic expeditions or you often encounter deep snow, a set of flotation tires is a good choice. However, if you only drive on public roads in the winter, regular-sized all-terrain tires will give you much better traction and overall better drivability.