You should keep the car reasonably clean so people can see it. During the Blizzard of '77 in Buffalo, some people had their cars run over by LVTP 7s (armored personnel carriers) from the local Marine Corps Reserve unit. During blowing snow, one lump in the snow looks like any other drift. The drifts were so high that I could just see over the top of the one in the street in front of my house from a second story window. Some cars were found in LaSalle park in the spring where they had been dumped along with the snow that they were concealed in.