|Fog Shadows at Somogy, Kaposfo, Hungary imaged by Schmall Rafael December 30, '08. ©Schmall rafael, shown with permission.
The floodlight at far right casts into the sky a twisted and apparently huge shadow of the church. Fog shadows can be a mixture of 2D shadow (like those on a wall) and 3D shadow (volumes of dark air). The unlit 3D shadow volumes appear dark because the surrounding lit water droplets scatter light towards the eye and camera.
Size can be deceptive. Shadows in the sky sometimes look huge because they are closer to you than the object casting them. Shadows of mountains and clouds can be similarly distorted even when cast by the nearly parallel rays of the sun.