We report on a new kind of rainbow scattering observed for 25keV He + -ions scattered under glancing angles of incidence from an irregularly stepped Fe(001)-surface. Polar angular distributions of scattered projectiles show an additional peak at smaller angles, which is ascribed to scattering at isolated downward steps on the surface. Based on classical trajectory calculations we identify the observed feature as a rainbow and deduce the interaction potential for fast ions at large distances.