Which types of surfaces can reflect radar signals poorly?

Sandy spits and mud flats can poorly reflect radar signals because these surfaces lack the necessary hard, smooth characteristics that effectively bounce radar waves back to the radar receiver. Radar signals reflect best off surfaces that have a significant contrast in material density and are relatively hard and smooth, such as concrete or metal. Sandy and muddy surfaces tend to absorb radar energy rather than reflect it, leading to weak or diminished radar returns.

In contrast, rough waters can create multiple surfaces that can reflect radar signals to some extent, even if imperfectly, due to the mixed wave heights creating a varied radar picture. Flat calm seas generally provide a stable surface but may not significantly enhance radar returns dependent on other factors such as vessel orientation. Areas with heavy fog might obscure visibility and complicate radar readings, but they do not inherently affect the radar reflection capabilities of the surface below. Therefore, sand and mud, lacking a solid surface for reflection, are particularly poor at returning radar signals.