Airborne ash that falls from an eruption cloud, and the resulting deposit. (Neuendorf, K.K.E. and others, 2011)
Even small amounts of fine ash fallout may cause respiratory problems in some humans and animals. Re-suspension of ash by winds may prolong the unpleasant effects of ash fallout long after an eruption. Heavy ash fallout may interfere with power generation and electrical equipment, damage air filters and gasoline engines, interrupt radio and cell phone transmissions, and greatly reduce visibility. The weight of very thick ash falls may collapse roofs, especially when mixed with rain or snow. (RI 2004-3)
