...unless you've got a lot of lift and TALL tires, I'm gonna start callin ya midget. Ain't a tire made, radial or bias, that'll keep you going when the whole underside is sitting on the snow and the tires can't find ground under em anymore.
That simply ain't true Steve, you're thinking of how you get through deep snow with radial tires... that is, ya' get a run at it and pray. That's because radials ride up on top of the snow... that's what they're designed to do. Then what happens is the radials dig in and leave you with your frame laying on top, wheels spinning in mid air. So what ya' end up doing is getting a run at it... hoping momentum will carry you through.
Narrow, traction-lug, bias-ply tires don't ride up on top of snow like radials... slow and steady, almost a crawl at times, is the way to run them through deep snow. If ya' feel a wheel start to slip you're tryin' to go too fast, you're allowing snow to get forced under the vehicle instead of around it. Time to stop, back-up, and start forward again, slow and steady this time. The tires should always be in contact with the ground, especially the fronts... the only way the truck and tires can ever get to the point where,
"the whole underside is sitting on the snow and the tires can't find ground under em anymore" is if you screwed up, likely tryin' to go too damn fast and pushed the truck up over the snow. Sometimes, to go 50 feet forward, I may end up going 150 feet backwards... but I get there, warm and snug in the cab. Heck, I've driven where snow was pushing up over the hood and I needed the wipers to clear it from the windshield. Drifted and hardpack snow means you need to "cut" a path through it... slow going, sometimes just a few feet at a time, but you get there. By going slow and steady I've never once been in a situation I couldn't back out of... never once.