One of the reasons to put tracks on a vehicle is to reduce the pressure it exerts on the ground. A bulldozer might weigh 15x as much as light truck, but if it has 75x the contact area, it would have (much!) lower ground pressure, and would be dramatically less prone to sinking into snow or mud or what-have-you.
Some tracked vehicles like bulldozers are available in extra-wide track versions to reduce their ground pressure even further. It wouldn't be surprising if most of the snow fleet is so equipped.
Let's say an human with height 170cm and hip width of 85cm (these are between the averages men & women) gives a rectangular area of about 1.4 m^2; the head and legs aren't as wide as the hips, but this doesn't include the arms, so let's take it as a guess of the weight-bearing area for a prone or supine human. This area times 5 psi is more than 5,000 kg (more than 11,000 lbs). So yes, I think it would kill someone.
Some sanity checks:
1993 Toyota 4Runner / Hilux Surf: 25 psi (https://en.wikipedia.org/wiki/Ground_pressure)
Caterpillar D6R LGP Bulldozer: 5 psi (http://www.ritchiespecs.com/specification?type=Con&category=...)
Some tracked vehicles like bulldozers are available in extra-wide track versions to reduce their ground pressure even further. It wouldn't be surprising if most of the snow fleet is so equipped.