Desert Sandstorm: Wind, Grain Density & Visibility (2D)

The 3D version of Desert Sandstorm orbits a sand-swept dune field from a free camera; this 2D companion instead fixes a side-on cross-section and puts the physics in front — a wind speed slider drives grain advection across a dune-height profile, a density slider sets how many grains are airborne, and a turbulence slider adds the swirl that lofts grains higher and deepens the optical path. All three combine through a Koschmieder-style extinction law (V = ln(1/ε)/k, with contrast threshold ε = 0.02, the same relation used to estimate real-world visibility in fog and dust storms) so the visibility readout is a genuine function of the controls rather than a cosmetic number, and the fog overlay darkens in step with it.