Ash Cloud Dispersal: Plume Height & Isopach Fallout (2D)

This 2D companion trades the 3D version's orbiting volcano for a side-on cross-section built to read the physics directly: the Mastin plume-height law converts mass eruption rate into a real column height, a drag-based terminal-velocity solver settles every ash grain by size once it detaches into the wind-driven umbrella cloud, and a live deposit-thickness graph accumulates exactly where each particle lands — reproducing the sharp near-vent peak and exponential downwind thinning that real ashfall isopach maps show.