Vertical shadowing occurs when which condition is true?

• A. It occurs when inland peaks overshadow the coastline.
• B. It is the effect of atmospheric conditions reducing visibility.
• C. It refers to the phenomenon where lower mountain ranges of coastal hills shadow higher inland mountains.
• D. It is a sensation of temperature contrast causing mirage.

Answer: (C)

Vertical shadowing is a terrain shielding effect along the line of sight: nearshore hills block the view to higher terrain inland. When the observer or radar sits on the coast, the topography of the coastal hills can intercept the radar beam before it reaches the inland mountains. Because the beam is blocked by this nearer terrain, the inland higher mountains fail to produce returns in that viewing sector, showing up as a vertical shadow on the display. This is a geometric consequence of relief and line-of-sight, not an atmospheric visibility issue or a mirage.