I've used those quonset hut shaped fabric garages and had very good luck. The snow just slides off them if there is too much.

Never let your car sit over dirt as the moistture in the soil will rust anything over it if the car itself is covered. Put down a waterproof tarp/poly for the car to sit on.

I have had to leave a car out during a winter or two while building another. Get a soft cover, then a waterproof tarp or polyethelene that extends all the way down to the asphalt/concrete/tarp so minimal moisture get underneath. I've used rope to keep the tarp/poly in place so the wind does not blow it off.