My buddy doesn't believe me it helps

 

...More contact? I really don't know...

 

it spreads out the load, increasing your foot print, better floatation.
This link explains it

 

Tell him to take his shoe off and go step into the snow. When he sinks up to his crotch(well hopefully you find a nice deep spot) walk out to him with your snow shoes on and tell him that bigger foot print makes for better floatation...

 

I was about to ask why people wear snowshoes... But bbp beat me to it

 

Two main reasons. Gives a larger footprint, but mainly as the flater tire comes off the snow and re-rounds it forces the packed snow out of the treads.

 

yep, like everyone else said, more surface area touching the ground, more traction. it's also why there is tread on the sidewalls of decent truck tires (like a BFG AT, for example). as you lower the pressure far enough, part of the sidewall because the riding surface, and it wouldn't do much good if it was smooth. (you'll never really see tread on the sides of car tires.) it works great in sand too. i've been stuck before in sand cuz i didn't lower my pressure enough. i just got out, dropped the pressure a few more pounds, and pulled myself right on out. just don't go too low or you'll blow your bead. i'm assuming snow is the same as sand, and for the sand dunes in michigan most people lower it to around 12 psi. i've heard down to 7 or 8, but i'd never go that low.

 

More surface area plus lower contact pressure. This trick works for driving on sand too.

 

I air down to 9 psi for very soft sand like out at Glamis and deep snow, it works well.

 

it depends where in snow you're driving..

if you notice rally racers driving down those snowy and ice roads drive on skinny studded tires.. Nevermind the studs, but the skinny tires CUT through the snow to grip the road..

If you're driving in deep snow where cutting through the snow would leave you high centered, you wanna air down.. but I find for city driving (especially when I was in a small car) high pressure gave me far superior traction..

I'm about to enter my first winter with my Yota, so I'll fool around with tire pressure to see what works best for me..

 

For city snow driving, 20-25 psi gives me the best traction. I slide all over the place if my tires are at 50 psi.

 

I had a set of Goodyear Ultra snow tires on a 98 Golf, and at 35 psi I had better traction than 25.. Even when the tires had 30% tread left, they liked having higher pressure

Now that was a small, FWD car.. I know for a fact my 4Runner will respond differently to tire pressure, but my point was about floatation. When off-raoding, flotation is good if you're in deep snow.. However on the streets, floating isn't ideal.. You want to grip either the road, or the hard packed surface below because it is more stable, and the best way is to cut through the powder/slush etc..

My point is purely "technical" and in no way includes driver skill or experience when driving on snow.. I drove my parents Durango in highschool, and in the snow that thing drove worse than my VW, especially when braking.. Big floating tires and a poorly designed ABS system made any stop at least twice as long as it needed to be.. in the VW I could lock the tires and dig through the snow and hit ashphalt, where the ABS in the Dodge would keep me on top of the slippery surface.

Sorry I strayed off topic.