The most critical thing to do is seek shelter, in a predetermined, safe area as mentioned above. The most ideal location is a basement or storm shelter. If you are located on an upper floor, do not position yourself under a heavy appliance. Once in place, hold on and protect your head. Always stay away from windows and open spaces. If you are in a vehicle or trailer, get out immediately and go to a more substantial structure. If there is no shelter nearby, lie flat in the nearest ditch, ravine or culvert with your hands shielding your head.