$3 at the Superwash, you get 20 minutes, a brush, and a really great feature called the spot free rinse. The advantage here isn't the "spot free" part, its that the water literally runs off like a slick coat of wax leaving nothing to freeze. I was gonna wash my little pig today, it was way up in the twenties here too

but I figured with a storm coming and some plowing ahead, hopefully, it would just be a waste.
The pressure washer shouldn't hurt your paint, mine works quite well, even though its only a 1500 pounder. Keep it off the decals