I will attest with almost 100% certainty that the snow pack in the wheel was the problem. had that happen to me last march, felt like the weels were coming off at 50MPH. Scared the bejeebies out of me!!!! The wheel shelf is huge and carries alot of weight if snow and ice is on it-doesn't take much-trust me on this. When you get stuck in a snowbank, you need to turn off the traction control to keep both wheels turning at the same speed, back out as slow as you can, and work with somebody if needed to get some traction spot.

I don't think you did any damage, clean the wheel shelf off and you'll laugh at it after the fact.