low air pressure in your tires. fill 'em up!
Power steering belt?
Bad steering rack? Bad steering gear? Pitman arm?
Loose or worn out power steering drive belt. Usually this is a loose or worn belt on the power steering pump. The pump works its hardest when the vehicle is parked or at low speeds so if there is a belt issue, it will happen then.
ignition switch in the steering column is faulty. Car would not start when the car is parked in the sun. Need to remove the steering to get to the switch.
Make sure the Rack & Pinion assembly bolts have not come loose. Also check the linkage from the steering column to the rack.
You cannot turn the wheel while parked. Try turning on the car, keeping it in park, and Turning the wheel if there is a lot of force needed to turn it, check the belt and fluid levels.
What makes you think it only leaks while parked. -
Look at the under carriage and check the ground where the vehicle is parked for a power steering puddle or stain.
The wheel has a whole in it.
Sorry, but it's awfully hard to find a parked car liable for an accident, even if illegally parked.
If the power steering fluid leaks out the steering would become very stiff, and perhaps "lock" if the car were parked.
Try putting on the emergency brake & turning the wheels one way while turning the key. If that dont work try turning the wheels the other way..if your parked on a steep hill you might even have to put a brick in front of the tires and let it roll a bit to remove some pressure from the wheels............hope it works