Regardless how deep the snow is, it has an an uncanny ability to find your electrical stuff and ruin it. Which generally sends your rig screaming uncontrollably off into the distance into something very hard with a spray of parts and cusswords as you get to ground zero and survey the destruction.
Just do a quick search for waterproof or plasti-dip.
Servos, receiver, battery pack. Receiver and battery pack can be put in a balloon, then a dab of RTV in the neck and a ziptie to seal it up. The servos can be ballooned as well, but they are generally exposed and prone to getting punctures. Plasti-dip works best.
Or, for servos, upgrade to water proof/resistant servos. That's your best option.