Besides what everyone else has said ..... when I was down in the SoCal desert, I got my van stuck in loose sand several times in a few minutes. It was across the road from an official campground, and the host had told me a few minutes earlier that it was ok to go in there and look around for a boondock site, so it's not like I did a totally stupid thing (duh). But once I got in there there was no place to turn around, except in very deep sand, so I had to keep going forwards.
It's a late model GMC Savana V8 van. I was able to rock the van out the first time. The manual says to take it out of StabiliTrack when rocking - not sure why??? In normal automatic mode, it goes into 1st gear at low speeds, and has tons of torque, so the rear wheels dig right in. Once I got unstuck, what I ended up doing was to put the transmission into "manual" mode, and use 3rd gear, and then it drove over the sand quite well without digging in. So, just another possible thing to try.