OK, here's a picture of the snowbank -- if you had a truck with a plow you could get through. Or perhaps even a few people with snow shovels. But it is pretty hard, compacted snow.

Not a great image (it's captured from video), but you get the idea.
Here's a map link to where this is:
https://goo.gl/maps/RDUDXWg954H2Getting above this (there's a little peak next to it), I could see that there were a couple more snow banks like this further along the road.
Here's another vid capture of the other snowbanks:

Another note: the road is *really* rough in spots. Risky for anything not designed for off-road use.