Eh? Ever see the tires they run on World Rally cars for snow rallies? They look like freakin' temporary donut spares, skinny little suckers. Yeah, they're studded too, but they use the narrow tire to increase contact pressure to get the tire to bite into the surface better. Same applies here. You can't get a 2-ton SUV to "float" on the snow short of a set of Mattracks, the tires WILL pack the snow under them. Sure that's fine, until you need more traction, in which case an aired-down tire will be less prone to bite into the packed snow and will just spin on top of it.

Seriously, airing up is the answer. You have better clearance, higher contact pressure, and better traction as a result. Not to mention the cold temps will have already knocked your psi down a bit.

Brent