Soft is a technical illusion. At low sun angles, the mountain’s coat of snow acts less like a mirror and more like a diffuser, as elongated paths through air load the light with reds and oranges while Rayleigh scattering strips out much of the blue before it even reaches the summit.
Yet the real switch is geometric. Ice grains, with their hexagonal lattice and faceted microstructure, present countless tiny prisms whose bidirectional reflectance distribution function, or BRDF, changes abruptly as the sun climbs; shallow angles send photons bouncing multiple times inside the crystals, promoting subsurface scattering that washes edges and lets warm wavelengths leak sideways into shadowed slopes.
Harsh contrast at a higher sun is not artistic mood but optical sorting. As incidence angles steepen, Fresnel reflection at crystal surfaces dominates, polarization grows, and albedo in the blue part of the spectrum rises, so shadows lose their color bleed, ridge lines harden, and the same peak that looked brushed in pastel now reads like a black‑and‑white sculpture carved by pure radiative transfer.
