About 28 inches here in Reston. That's enough I think that our usual snow plow (pickup truck with blade) won't be much use. The cul-de-sac has cars on both sides. Usually the plow can scrape snow to the ends, leaving a ridge behind the cars that you have to shovel. With this much snow I don't think the approach will really work. We'll see--I remember an early snowstorm, maybe late 70's, where we waited and waited until finally a front loader came in. That may be necessary this time.
The ethics of snow are interesting--to dig out your car you can either throw the snow into the drive path behind the car or carry it to the front of the car. The first hurts the rest of the people in the cul-de-sac, particularly those who live further up the cul-de-sac, making it harder for them to get out. The second hurts the back.
So far I've seen two four-wheel drive vehicles, one pickup, one jeep, make it out to the road, both after significant trouble; two other four-wheel SUV's tried and failed to make it out. Wife and I are reconciled to being house-bound for another day.