Fig. 4From: An automated ash dispersion forecast system: case study Popocatépetl volcano, MexicoEruption 14:51 UTC, 14th June, 2015. Observed ash, red polygon according to the Washington-VAAC. Forecasted ash concentration, coloured area in mg/m3(see legend). VAAC image taken from the VAAC-Washington webpageBack to article page