O/H parked her Volvo last night on a very light dusting of snow. Parking brake on, left in gear and sitting on four newish Michelin Cross Climate tyres. The driveway has a slope of about 15 degrees. Next morning, I found the front had slid down about four feet but the back had slewed round clockwise and down by over eight feet! I had a devil of a job manoeuvring the car out with only a total of about eight feet of clearance front and rear!