Atmospheric dispersal of a gas denser than air can threat the environment and surrounding communities. In complex terrains, microscale winds and local orographic features can have a strong influence on the gas cloud behavior, potentially leading to inaccurate model results if not captured by coarser-scale simulations. We introduce a methodology for microscale wind field characterization and validate it using, as a test case, the CO₂ gas dispersal from 1986 Lake Nyos eruption.